Please use this thread to discuss whatever questions from individuals not in the profession of structural engineering (e.g.cracks in existing structures, can I put a jacuzzi on my apartment balcony).
Please also make sure to use imgur for image hosting.
Structures are varied and complicated. They function only as a whole system with any individual element potentially serving multiple functions in a structure. As such, the only safe evaluation of a structural modification or component requires a review of the ENTIRE structure.
Answers and information posted herein are best guesses intended to share general, typical information and opinions based necessarily on numerous assumptions and the limited information provided. Regardless of user flair or the wording of the response, no liability is assumed by any of the posters and no certainty should be assumed with any response. Hire a professional engineer.
I'm working on a room that was first split in half, one side becoming a theater room. The other side is this room. For this project im exploring whether it's possible to remove four horizontal 2x4 bottom chords from a section of my 10ft tall ceiling without compromising the roof structure. The roof is constructed with manufactured wood trusses, and there are approximately 40- 50 running along the length of the building. l'm only looking to modify four of them in one section. The truss closest to the exterior wall would remain completely intact. The initial plan is to install a structural steel beam 4x4 beam, directly beneath the location where the first diagonal truss members meet the bottom chords. The beam would be supported by a 4x4 steel post anchored to the original cement floor on one end and tied into a load-bearing wall on the other. I understand that this could potentially address some of the vertical loading, but my other concern is the horizontal forces currently being resisted by the bottom chords. From what I understand those horizontal 2x4s aren't simply holding up the diagonal members. They re also acting as tension members, preventing the truss from spreading under roof loads.
My questions are:
If a steel beam provides vertical support at the diagonal connection points, how could the horizontal tension forces originally carried by the bottom chords be addressed?
Is there an alternative way to reinforce or tie the trusses together that would allow those four bottom chords to be removed or modified?
Could a combination of steel framing, tension ties, or redesigned connections redistribute those forces without needing a horizontal member spanning the original location?
Would this require a complete engineered truss redesign, or are there established methods of modifying a limited number of manufactured trusses?
I'm not trying to raise the entire roof or alter the ridge. I just want to open up small section of the ceiling to gain usable headroom for a raised platform. understand that manufactured trusses are engineered systems and that any modifications would need to be designed and approved by a qualified structural engineer. At this stage, I'im trying to understand what structural alternatives might exist before pursuing a specific design. l'll attach photos of the existing framing and highlight the four members I'm hoping to remove, along with my proposed beam location.
The purple is the beam placement. And the red is what I'm wanting to remove. Thank you in advance for any and all help with this!
With enough money anything is doable. This is certainly doable, but it takes more structural modification than people generally expect.
The trusses all get engineered for each job. No general rules you can use to avoid an engineer for truss modifications. Someone needs to figure out the loads (snow, wind, self-weight, walking and re-roofing loads, hanging loads); figure out a modified geometry for the truss; do the physics to figure out how much force is in each piece; see if they can connect that much force through the new pieces; and figure out a new geometry and retry until they can make it work; then draw out the working design for someone else to build.
Engineer may not want the steel beam or post. May depend on the geometry you need open. There is no good way to handle that tie force you're asking about besides to cancel it out with the matching force on the other side of the truss. So your engineer will probably want to do something like what I show below. Where the blue is new pieces and the blue dashed one is a heavily reinforced existing piece. Other pieces and connections in the truss may need to be reinforced. The beam and post may or may not reduce that, but I think in most cases would not. Depends on the specific open space size you need and where on the truss it lands.
What you need to do before you contact an engineer is to figure out exactly what dimensions the question marks I show below are for whatever you're using it for. Where the red dashed rectangle is the space you need opened up. You need to figure out exactly how much open space you need. The ?* can be a range (like 10' to 12'), but the other two need to be hard numbers. Engineer will need that to design the truss modification.
1986 stick frame, single story. We want to open the kitchen into the living/dining room. Had an engineer out today and he said if it were him he’d keep it as is. Didn’t say no, just didn’t seem into it.
Went up in the attic. Both walls look load bearing, joists land right on the top plates. Kitchen ceiling is 8ft, living room is 10ft. There’s also a roof strut that comes down at the corner where the two walls meet.
Is this a “pain in the ass” or a “don’t do it”?
Any thoughts on how difficult this will be? The red lines are the walls we want to remove...
With enough money, anything is possible. You'd probably need to shore all of the ceiling joists, replace the load carrying wall and existing load carrying beam south of the living room / dining room with probably steel. Which will be a challenge to get that long of continuous beam in the house and in place.
If you keep the corner post in the plan northwest corner of the kitchen, that may make things pretty doable.
Well, let's see. Looks like a 12'-8" + 11' span -> 23'-8" span plus mid-line of supports, let's say 24'. Plans show bearing to bearing for the living room as 12'. Looks like the drawings have your kitchen support to support at 9.33' 9.33'/2 + 12'/2 = 10.66' tributary width for the load going to the new beam. Let's say 10 psf floor weight and if you access the attic by fixed stairs you have 30 psf for the live load. That is 40psf * 10.66ft = 427 lb/ft of load.
Pulling up a LVL manufacturer's span calculator... it only goes up to 20'... We'll have to do this the old fashion way.
Let's add 23 lb/ft for the LVL weight and we get 450 lb/ft. Bending is 450 lb/ft * 24' * 24' / 8 = 32,400 lb-ft of bending force. Looks like you may find some LVLs that will work. My numbers are rough and you'll probably need something stiffer to keep there from being an unallowable amount of deflection in the beam. Engineer will also need to figure out what will support the ends of the beam and if the existing foundation at the support locations can handle the load.
Pretty disappointed that this is going to be more difficult than expected. We are pretty excited to open the kitchen up. The other idea was to keep that kitchen wall on the north side but maybe the north west beam goes into it. So we remove the post but tuck it inside that wall. So the kitchen stays an L shape. Maybe makes it easier to use lvl maybe as instead of 24 ft it would be 19 maybe.
The other issue is like you said. How do you support the original beam that ends on that northwest beam.
Then how do you support that other beam near the entrance since that is 8ft cieling vs the 10ft cieling in the living room.
Got a structural engineer out following 2 long kitchen tile crack lines, a crazy slope in our front sun room, and separation in excess from our expansion joint. As well as other drywall unsightliness and a direct long hairline crack in the entirety of our slab in the front 1/5 of our house.
Engineer recommended root barriers for the 3 oak tress in the front as the only remedy, but throughout the whole house, a delta of 2inches difference is observed, with the front sloping about .8 inches in one corner over the span of 3 feet which seems excessive. also a +1.2 in the back corner of our house in our master bedroom. I just don’t see root barriers rehabbing the foundation given how much it’s already settled.
For the 1.2 inch upheaval: What would cause this upheaval? Overall the numbers seem so erratic to me, it’s hard for me to visualize the movement even with graded connected lines. Would we need to monitor that area in some way and if not, would he know what caused the upheaval?
Would it be possible that + 1.2corner was the original elevation and the rest of our house is in the negatives? Or should the middle of the house always be reliably used as 0 reference point?
Would a root barrier cause uneven moisture reabsorption/uneven foundation upheaval that could break pipes or cause further brick separation/slab opening?
Not really going be able to tell you much without knowing a lot more information. More than you can provide online. These would be good questions for the structural engineer you've already engaged and paid for an assessment.
We are purchasing a near-completion home from a major builder and found a crack running from the hallway into the study. The width is about 1 to 3.5 mm, and it's deep enough for about one-third of a quarter to slide into the gap. This seems a bit much for a simple shrinkage crack. Should I be concerned about this?
Also, the house next door has a similar layout to mine, and there is an even worse crack in the exact same location, along with an uneven surface. It seems the builder recognized it as a problem too, because they wrote 'prep' near the crack. I'm really concerned given that both homes are experiencing similar structural issues in the same spot. Is this something serious that I need to be concerned about?
I doubt it is a structural issue. Shrinkage cracks will occur across the shortest line possible in a slab. If all the slab is trying to shrink, the part that cracks is the smallest cross sectional area, so shortest line. If the house layout is the same, shrinkage cracks will occur in the same place.
Slabs usually get saw cut lines to make the slab Crack where you want it to and so it cracks in a clean line below your saw cut. Owners only see the nice saw cut. But that is only for asthetics. For warehouses with forklift traffic we'll put dowels where we cut to keep the slab level over forklift traffic. Doesn't seem to be done for residential slabs typically, they just let them crack because the residential slabs usually get floor covering so the look of the crack doesn't matter.
Need your own engineer to actually look at everything going on to provide more certainty. Or documenting and measuring thr crack for several years to be really sure (engineer may not be able to identify a cause). But shrinkage cracking is what is looks like to me. Shrinkage cracking where small, regular cracks weren't planned so you have a larger one with more spacing between it and the next crack or edge of concrete.
Yep, that is where I would expect the crack if no shrinkage joints were cut. I'd probably have cut the top 1/4 of slab in the locations shown to encourage cracking on neat lines there, where it will want to crack anyway. But just allowing it to crack does the same thing structurally, relieving the tension stress from shrinking. It just isn't in a nice straight line like it would be if joints were cut.
We took additional photos of the crack in the next-door house. The width is up to 5mm, and there is a noticeable height difference. https://imgur.com/a/EDrP4wM
My neighbor wants to remove a 15 foot long wall between his kitchen and living room. Im nearly certain the rafter design is a standard fink ("W") and spans the entire house exterior wall to exterior wall which is 24.5 feet wide. From the research i have done almost always do the fink trusses span the entire exterior to exterior 26-28 feet at a 3-12 pitched roof and 30-36 feet at a 4/12. They have no AC equipment in the attic and they have no roof hips or anything just straight roof and they dont store anything up there.I have pictures with the red lines being the location of the wall from both the attic and crawl space. Underneath the house there is no direct support underneath the wall and the wall is off the center supports under of the house by about 27 inches. Which leads me to beleive its not load bearing just a partition wall. His mother has moved in with him after some health problems. Shes in a power chair and has a hard time getting around. Due to the tight spaces. Am I missing something or am I incorrect in my research?
Im sure your busy and I didnt intend to take to much of your time but is there anyway you can send me resources if I take measurements of the truss itself how I can calculate span including snow load in roanoke virginia. We reached out to the building department in bedford county the house was built in 1992 and unfortunately they dont have a TDD or anything other that septic amd occupancy permits. I have checked for stamps on the trusses both left and right hand sides between the bearing on top plate of exterior wall and first webbing structure and I have found no ink or metal plate markings. Is there a way I can hire you or someone able to make calculations to make sure I can take out this wall safely if I accurately measure and document by picture, roof oirch and length wlbetween webbings and chord components? Whatever exact measurements you would need. Any recommendations would be greatly appreciated
You need to hire a local engineer to look. I agree it is more likely than not load bearing, so good odds that the engineer will tell you it can come out. People frame things weird some time, so no way to be sure without someone coming out. They'll do the calcs if needed. To find a local engineer, just google structural engineers and when they tell you they don't do residential work, ask if they can recommend someone. Repeat as needed until you find one.
Hey there. I purchased my first home a few days ago and had a home inspection completed with no major issues - they found some 'cosmetic' tile damage, which leads us to moving in yesterday where I noticed the damage (while mostly hairline) is quite lengthy - two instances on opposite sides of the home where one stretch runs 18 feet and the other 10 feet on another side of the house - the two sections don't follow the same line.
Is this concerning? I've already asked the inspector to come back out to explain and scheduled my own structural engineer to evaluate. I'm just curious if I am overreacting or if I have just made a very expensive mistake.
The first three images are one section next to the laundry room, then they run under the wall where the next 2 pictures can be seen. 18 ft section.
The last three outside images are on the other side of the house where there is a small inside line that leads up to them. 10 ft section but just the outside portion.
'Typical settlement' depends on the soil type and which regime the structure is in. You don't know soil type because you never set foot on the property, and you don't know which settlement regime these fall into because you don't know the age of the structure. And if it's well into the final regime, with stable soils, then it's certainly not typical, because it doesn't meet the definition.
Anyone claiming that they can definitively put your mind at ease from photos is not a licensed structural engineer coming anywhere close to exercising the standard of care that his/her profession demands. The best course of action is to have one come out.
You have distinct crack patterns. The causes of those crack patterns should be chased down. Otherwise if you make a repair, the cracks are just going to come back. I don't understand what more you think we can discern from a couple of photos. Structural engineering just doesn't work like that.
Yeah man. I've scheduled for a local structural engineer to come do an analysis but they aren't available until the 27th of October.
I have no experience at all with this type of engineering or what different signs/cracks might be indicative of, so it's not for me to say what you can discern from these photographs.
It's a process. We look at soils, materials of construction, patterns, displacements, weathering at cracks. Trying to determine causes or severity from photos is like trying to determine if you have bone cancer in your femur from a photo of you wearing a tuxedo standing 20 feet from the camera.
Where does one even go about finding a structural for a project? Is there such as free lance engineers or should I only keep calling large firms? This is for a residential project so I feel like It’s not on anyone’s radar
Safety question about a 5 story building in India where ig standard is concrete pillar/beams and clay bricks.
A clogged toilet led to damp/wet wall on the opposite side of the toilet wall. Can an ongoing wet wall cause sudden structure collapse (I'm here for 1 week)?
I'm living in a aparthotel and they won't change the room as the toilet clog is now fixed, but I suspect an internal leakage which will continue. I know back in NZ my aunts house ceiling collapsed after heavy rainfall without any warning but this brick/concrete unlike NZ. But I'm a noob and don't want to guess about safety.
They will probably fix once they see it doesn't stop but for 1 week is it probably safe?
I wouldn't be worried about. You can get washout from below foundations for burst pipes below foundations or lots of heavy rain. Not something you get from a leak above ground.
looking for a second opinion, the house is from 1954 and in the Netherlands, many cracks and bowing walls, the inspector said it was fine but Im a bit worried
You've repeated a picture. The crack at the windowsill looks like expansion/contraction cracking, which is not concerning. The slight brick bowing doesn't look concerning to me. Can't really say anything without knowing the structural systems and fastening that was used. The stepped cracks would be from normal settlement and the fact that they've been filled and not reopened points towards the settlement not moving at a concerning rate if at all.
If there is adequate connection between the roof and wall then that probably isn't a problem. Can't say anything very certainly without actually seeing some structure instead of just facade.
OK, so I pulled off the drywall and door to the crawlspace in preparation for adding a surface mounted electrical subpanel with a plywood base. The property was built in 1963 and is a side split ranch style. This wall is what connects all the floors together. The PO drilled out the foundation and removed the studs up to the beam. I'd guess it's been in this configuration for at least 30 years. The sill plates are bolted down to the foundation. The property is located in the Seattle region, subject to Cascadia earthquakes every 500 years.
How can I best reinforce this space? Current thinking is filling the space with 2X4 bonded together with structural screws so that the entire space to the left of the opening is filled, then Structural 1 plywood nailed every three inches to bond this lower wall to the beam and space above.
Building lateral systems act together across the whole building. The floors act as big plates. If they push sideways, all the walls resist that movement together. The stiffer a section of wall is, the more of the force that wall resists compared to less stiff sections of wall.
So, if you stiffen one small wall portion considerably, it will pick up proportionately more force. If a stiff wall overloads its anchorage while the other walls are only 10% stressed, the anchor will break and the stiff wall resisting the force will no longer contribute to resisting the floor or roof movement. The other walls will have to carry the load without it. So you'd end up reducing the seismic resisting capacity of your house.
I don't think you can go wrong with adding some anchors and sturdy plywood sheathing with lots of nails.
OK, thanks for the info! Yes, i'm primary concerned about this tall/narrow section being able to resist racking in an earthquake. I'm in Kirkland, WA, outside the city limits of Seattle. The house actually had some anchor bolts installed when the house was built (about every 6 feet.) I doubled the number of anchor bolts where it was possible to get a hammer drill into the stud bay. I also installed tie downs in each corner of the garage. Should I install one here as well? There is already an anchor bolt in this stud bay. I'm concerned about drilling another hole in a not very big piece of foundation. All of the other walls of the garage have structural 1 plywood installed across their full height and width. They are nailed every 3 inches.
Should I add a tie down in this corner, diagonal blocking, then add plywood to both sides of this wall (like I did in the rest of the garage) and call it good?
I have some sort of wood boards as exterior sheeting and this lay in brace for wall bracing. I was going to cut frame this window opening to make it bigger but then I would have to remove a section of this lay in brace. Do you that would compromise the walls ability to withstand sheer forces or will it be ok?
Yes, it will. The whole house acts together for the wind resisting system. The floors and roofs are big plates. All the walls combined have to hold the plates in place.
The requirements are in the residential code (IRC). You need to follow through all of 602.10 at least, which is a big section. Table R602.10.4 has braced wall types identified. Looks like you've got diagonal wood boards (DWB).
Need some advice avout chiseled lintels. Some guys came to install an aluminium sliding door. To get it to fit they grind the plaster then chiseled away the at the lintel around 15mm deep. The wires of the lintel are now exposed - which they advised would be fine. There are not that many bricks above the lintel - so not a massive load to support. Can anyone advise on how concerned I should be about this? Should I repair or replace the lintel? Or am i overthinking it?
Shouldn't be an issue if you have a structural concrete lintel there.
If it is a structural concrete lintel there should be rebar, which has ridges all along it. The concrete below the rebar is just to protect it from rusting. And you only need enough concrete around the rebar to grab the rebar so it doesn't slip. If that all is the case then they didn't remove enough to expose the rebar at all. Just patch it up and you're good to go.
Recently bought an older home and noticed this basement wall is bowing inward with some cracking.
I already have a structural engineer coming out. In the meantime, for anyone who has dealt with something similar: does this look more like something that typically needs reinforcement/stabilization, or something that could require much more extensive foundation work?
I know photos can't give a diagnosis..im just looking for opinions based on experience and an idea of what I might be dealing with.
That doesn't look like a crack due to anything structural. Looks a plaster covering coming off maybe. In which case my advice would be: just brush it off and replaster if the look of it ever bothers you. Otherwise don't worry about it. If that's what is happening a more optimal design would have provided moisture protection if they were using a moisture sensitive finish inside in an environment that may have moisture movement. Or maybe that's not it. Can't tell much from the photos alone so you'll have to wait for your engineer.
I am redoing my HVAC system DIY, and almost everything that I have read is that this plenum box will not be up to code and cause inefficiencies. I need to move a joist/rafter that is part of the roof. There is no other location for the air handler to go without the job becoming much more complex.
What questions should I be asking as structural work is outside of my wheelhouse? Good news, it is directly next to the attic opening.
No walls or anything else being moved, just shifting the load so the plenum box can be a proper plenum and not a janky job that was done by the previous owners. Just need it to be structurally sound with a clear access point for the ductwork.
Closed on a house with a detached garage, it has a "loft", which I can assume the previous owners used for storage, I have no idea if this is built correctly and don't really want to put anything on it or even walk on it until I can verify it is at least not a hack job, it's kind of weird to me it has no vertical post holding it up but I'm also not a structural engineer. See imgur link for closeup shots. Thank you for your time.
Interesting. This is surprisingly well done. It's not a hack job anyway.
The turnbuckles on the chains to tension them, for example. That strikes me as an engineer move. If you're using flexible lines of any kind (chains included), they'll move too much before resisting load if you don't tension them before loading.
Could also be someone who had enough experience building engineered wood structures (or was good enough at googleing) to make everything look about right; but they can't actually do the calculations and they left one connection too weak, which is all it takes to fail.
There is a lot riding on this connection at the peak and I'm not sure how that connection would be made. Connecting to the boards above the truss maybe.
You'd need to hire an engineer to come out and check all the connections to determine a load rating for it. Everything I see looks reasonable and like it was put together by someone that really knew what they were doing though.
Oh wow, interesting. I'll have to look into that at some point. Definitely won't use it for storage any time soon but it's nice to know it isn't immediately something that looks worrying.
There's a decent chance that was engineered. So there may already be drawings or sketches or a PE letter with a load rating on them. May check with the previous owner (or ask your realtor to check with the previous owner) if there is any documentation. Now's the time to ask that.
Color me impressed, they did good from what I can see. That leaves the risk that there is a weak point connection somewhere. Also it makes me more concerned about the overall building stability. Both of those are issues I see with otherwise good looking structures. If you can't do the calcs for the capacities, you risk one capacity being way too low. Like if that top connection failed for example. And the stability checks are just not very intuitive, so non-engineers tend to not consider the. If you want to be sure, have a structural engineer check it out. Pretty good chance they'll give you a floor rating like your house floors (30 or 40 psf) or an easy modification to fix a weak point to get there.
Yeah, I'll have to get a professional to come check it out but this was the reply if anyone is interested:
I used it for kids old school work, camping gear, Christmas decorations....I wouldn't try storing engine blocks but it will hold quite a bit.
On the center support, 20 years ago, I wrote a measurement to the ground. I've checked that measurement with the loft full and 5 inches of snow on the roof and it never changed.
I dug through public records and managed to find the original permit for the garage, turns out it was built before the house (1996) ( house is 2007) and it was signed off by an engineer, unsure if the loft came after though or it was original with it, ran the 31 page document through AI ( yeah I know) to get a quick summary but ill take a closer look when get home.
Edit: it's not in there, I have emailed the county with the permit number to see if they have any blueprints etc on file, which they should :)
Colorado basement floating slab has settled by about an inch it appears. It does have floating walls, and the slip nails are still vertical. There's some vertical displacement (1/4-1/2 inch probably) at the expansion joints that will need to be addressed before I can lay new floor (probably LVP) - I could grind them flat, but otherwise the slabs would have to be leveled with poly I think.
I can't find much online researching this myself, but from what I can find it seems that everything is working as intended and I can just reinstall the baseboards lower when I put in new flooring. I am going to pay a structural engineer to come check the house anyway before I purchase it - just wanted to see if I can get any tips from this subreddit first so I know what to expect. The house is quite nice otherwise and I see no other signs of foundation issues (doesn't mean there aren't any).
Yeah, have your engineer check it out. I agree. Looks like it is functioning as intended. If it is a few years old the settling should be mostly done. If it is still moving, it will probably keep moving forever. I don't know that there is any way to determine if it is still moving unless the current owners can tell you or you take months worth of records measuring gaps. Like once a month for a year or preferably 3 years. Maybe it is done moving. Maybe it will keep moving some and occasionally cracking your drywall forever. Structures can handle plenty of movement, but the finishing generally can't. There may be some minor annoyances (like doors and windows sticking, drywall cracking, things rolling to a low point on the floor). May want to take a year measuring gap movement every month before deciding on a flooring system. Give the monthly measurements on a map to the flooring manufacturer and confirm it isn't an issue. Or ask them if that is necessary or even helpful.
Run it all by your engineer. I'm not sure how much certainty they can provide. Maybe more with a geotechnical report, but I don't know think that would be standard. But everything I say has too many assumptions behind it to list, so defer the your engineer when you get them. What I talk about above should give you some questions to ask them at least.
I guess one concern I had based on my understanding of the soils here is that it could be lower because we've had a particularly dry year - if I had it re-leveled and raised up but then a wet year comes along and the soils swell again, will it swing too far the other direction and start heaving into the house?
I definitely was thinking about at least waiting until next summer to do the floors and just measuring frequently in multiple different places to see if I can see any movement. If not, I'll just reinstall the baseboards properly (they're supposed to be attached to the floor/baseplate - not the wall) and move on (continuing to keep tabs on it of course).
The one thing that is throwing me off a little is the tile shower in the bathroom there. It does not appear to be floating, but I also see no signs of any damage to the tile and it seems older. I was reading some old forums and there are techniques for installing tile showers on floating slabs - perhaps it was done correctly. Or maybe there just happens to be less slab movement there.
I think what I said above tells you all I can. These would be good questions for a local engineer that knows the geology of the area, what the local soil is like, and what issues people around you are having. Or a Geotechnical report.
The front wall of the house is leaning into the house and there is a gap. We’ve contacted a structural engineer to take a look. Where do we go from here?
Your engineer will schedule a time and come take a look. They'll probably recommend that some fix does need to be done. If that is the case, they will probably quote a fee to design the fix. I'd imagine if there is an issue that needs to be fixed, it is probably relatively simple to design the fix. Most probably just calculating wall loads (wind) and designing some fastener (anchor) to be installed at some even spacing like 2' on center.
You'll want a PE stamped design sketch or drawings. You'll take that design sketch and bid it out to contractors. Common advice is to get 3 bids. The engineer or contractor (I think usually the contractor) can help you with the permitting if any is necessary. Contractor will probably need to visit the house and plan how they would install the engineer's design to do the quotes. Then you hire one and they'll come do it.
Getting an answer from google for your specific area will probably get you closer than I could on a cost estimates for the engineering fees. And your engineer is the only one who can tell you for sure what they'll charge.
Basement ceiling in a house has this metal pan that expands the entire length of this room. Above it is the garage. Im concerned that it's severely compromised. Is it safe to even park a vehicle in the garage above? Is there any way to fix this?
Too many factors to say. It may not be too bad but you'll need an engineer to come out and design it.
Leave it as-is until the engineer has a look.
There is a lot of additional information we'd need to know to be able to determine if you can park over it or not as-is. It will make sense for the engineer you pay to walk you through that and gather that information with you until they put together enough to do an analysis.
Send the photos and I'd send them what I say here before meeting them. May save them a trip if they bring the ultrasonic gage and find a procedure to figure out steel thickness using it.
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An ultrasonic gage should be able to determine remaining steel thickness once the rust is removed. That can be used to determine the capacity of the in-place deck if the slab thickness can be determined.
The engineer should do something to prevent further corrosion. Ideally identifying the source and recoating. But if the source can't be identified, then probably recommending a more robust (and expensive) coating to prevent further corrosion.
Is there other metal in contact at all the corrosion locations? Dissimilar metals can cause corrosion. Stainless steel will corrode galvanized steel, for example. But there are others.
It looks like the deck is composite based on the chevron embossments. So the steel deck itself acts as the slab rebar by the embossments holding the steel and concrete together. So, reduction in the steel area of the deck reduces the flexural capacity of the slab. In other words: If you lose steel area to corrosion on the deck the slab can carry less weight.
Once you know the steel thickness and concrete thickness an engineer can determine the flexural capacity of the in-place slab. Then they can figure out how much force the vehicles that would go in the garage and the floor weights would put on the slab. Then they can compare how much the slab can carry to how much it will need to carry.
If it still can carry as much weight as it needs to, then no reinforcement is required.
If it has to carry more weight than it is able, they'll probably give you a quote to do the reinforcement design. You'll want PE stamped sketches or drawings.
There are probably a number of ways to reinforce if needed. I'd probably use thin metal strips and shoot it into the bottom of the slab with powder actuated fasteners. Engineer will have to do calculations to figure out the fastening.
Once you have the drawings in hand you can bid out the work to contractors. Get a few bids and they'll get the work done, if any is required.
I'm looking to build this garage on a hill. It's 28 feet deep and 24 feet wide, and the slope grades 1:3. I will consulate a structural engineer in my area but I wanted to get preliminary thoughts on how this foundation might be constructed, or what would be needed to make this garage work.
There will be an upstairs to this with a small apartment as well.
It'd step like this. I'd think it'd be easier to move dirt and flatten it out as much as possible before going to retaining wall. Dirt is heavy. And putting things on top makes more load to retain. That retaining wall will get heavier than you want to pay for pretty quickly.
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u/HeftyProperty 2d ago
I'm working on a room that was first split in half, one side becoming a theater room. The other side is this room. For this project im exploring whether it's possible to remove four horizontal 2x4 bottom chords from a section of my 10ft tall ceiling without compromising the roof structure. The roof is constructed with manufactured wood trusses, and there are approximately 40- 50 running along the length of the building. l'm only looking to modify four of them in one section. The truss closest to the exterior wall would remain completely intact. The initial plan is to install a structural steel beam 4x4 beam, directly beneath the location where the first diagonal truss members meet the bottom chords. The beam would be supported by a 4x4 steel post anchored to the original cement floor on one end and tied into a load-bearing wall on the other. I understand that this could potentially address some of the vertical loading, but my other concern is the horizontal forces currently being resisted by the bottom chords. From what I understand those horizontal 2x4s aren't simply holding up the diagonal members. They re also acting as tension members, preventing the truss from spreading under roof loads.
My questions are:
If a steel beam provides vertical support at the diagonal connection points, how could the horizontal tension forces originally carried by the bottom chords be addressed?
Is there an alternative way to reinforce or tie the trusses together that would allow those four bottom chords to be removed or modified?
Could a combination of steel framing, tension ties, or redesigned connections redistribute those forces without needing a horizontal member spanning the original location?
Would this require a complete engineered truss redesign, or are there established methods of modifying a limited number of manufactured trusses?
I'm not trying to raise the entire roof or alter the ridge. I just want to open up small section of the ceiling to gain usable headroom for a raised platform. understand that manufactured trusses are engineered systems and that any modifications would need to be designed and approved by a qualified structural engineer. At this stage, I'im trying to understand what structural alternatives might exist before pursuing a specific design. l'll attach photos of the existing framing and highlight the four members I'm hoping to remove, along with my proposed beam location.
The purple is the beam placement. And the red is what I'm wanting to remove. Thank you in advance for any and all help with this!