Foundation Overkill and Appropriate Beam Sizing

Kevin Castaneda · 2018-02-12T07:21:53-08:00

Hey BP friends,Backstory:I'm in process of rehabbing a 1920s house in San Antonio, Texas, which has a cedar post pier & beam foundation. The house is 1600sqft total with a second story being only 500 sqft. The foundation is very level despite its age. The foundation beams are all 4x6" treated beams and one small interior section of the foundation has 4x4" beams.In San Antonio, an engineer's assumption of the foundation design and subsequent inspection is required in order for the city to issue a foundation permit. I've had several foundation repair companies provide their estimates and some estimates also included the cost of the engineer assumption... It was recommended to me to have my own engineer perform the design, that way I could take their plans to any foundation repair company and get an apples-to-apples comparison. Thinking this seemed like a good plan, I paid $500 for the engineer's foundation inspection and $200 for them to design the repair. This engineering firm has experience with foundation repairs and was recommended by a local foundation company.Dilemmas:The engineer's report says the cedar piers show signs of water damage/decomposition indicating they should be replaced.They also say the beams are undersized and should be upgraded. The recommendation is 53 new 12" diameter concrete poured piers. The recommended average beam size is (3) 2x8" with the largest being (3) 2x10".Before sharing the engineer's report, most companies quotes were around (45) 8" concrete piers for $12,000... These companies also pull an engineer's assumption of the design (...which I'm not sure how they manage to do that since it doesn't look up to code???)When sharing the engineer's report with the foundation companies, one company said the largest beams they normally do are 6x6 and that any larger is overkill (p.s. these guys normally pull permits as well). That company quoted me $18,000, and this was only using 6x6 beams on part of the foundation, not a full beam replacement.Another well-rated foundation company (who recommended the engineer) recommended not doing anything since the foundation is so level. I've also had contractors recommend that unless the engineer says the foundation is condemned, then the existing foundation has more life left in it.I feel stuck trying to figure out what should to be done, to what specifications, and whether by not repairing the foundation it would derail the home sale? Any recommendations on a course of action would be extremely welcome!Considerations:Would the average person buy a 1920s house that hadn't had the foundation updated?Will the home inspector get under the foundation and ask for an engineer's report? If we did nothing, I'm concerned about having to perform the foundation repair on the back end and whether that would screw over the new drywall/painting, re-hung doors/windows, and bathroom tile work all just done to the home?How would you handle this foundation repair?The Code:It seems most states uses the 2015 IRC guides for residential construction. Unless I'm reading the it wrong, it sounds like these would be the appropriate code sections for the beam/girders and that in terms of sizing the engineer is correct.https://codes.iccsafe.org/public/document/IRC2015/...R404.1.9.2 - Masonry piers supporting floor girdersR602.7(1) - Girder Spans and Header Spans for Exterior Bearing WallsR602.7(2) - Girder Spans and Header Spans for Interior Bearing Walls

Jim Goebel

Real Estate Investor · Des Moines, IA · Member since 2016 · 922 posts · 533 votes

8y

@Kevin Castaneda

Hi Kevin! This one my be up my alley. Caveat though - I'm not licensed in your state, so ... I'm going to keep this more general and as much business focused as focused on the 'nuts and bolts'.

I'm one of these engineers that has gotten my structural experience through doing various residential projects. I have a lot to learn but have gotten into some good projects where we had to fix settling issues, installing structural steel beam/posts, and replacing numerous joists/rafters. In a sense, the rehab type projects tend to be more involved/intensive than new construction, which is what you're running into here.

Thanks for all the info and I hope anything I can add may be helpful in advance.

Firstly, there's a couple considerations here. Firstly, from a business perspective managing risk and it sounds as though you're selling the place, so trying to obtain the highest sales price, and/or best value from your decision. IE: you spend 18k on the project but only get 5k in increased sales price, that wouldn't be worth it.

I can't really speak to that side of it because I don't know your market. However, I would think it'd depend on what else is out there and if you're dealing with a typical buyer that expects things to be 'perfect' or not. Here in Des Moines there's a lot of old houses and if you feel like you've taken reasonable actions/managed risk and been transparent, I'm not sure from what you're describing there would necessarily be any major downside impact on the sales price.

There's always also the prospect of doing things like offering owner financing, selling on contract, etc - that can help to give you leverage when it comes time to sell and defending if the buyers choose to send in an army of inspectors/engineers etc.

So here's some info to 'arm' you with in terms of loads, etc.

If someone is saying the beams are undersized in my opinion they should offer more specifics on that.

The ways that a beam can fail are important to understand. The two most common ways that a beam can fail are due to compression (ie load being more than capacity) , and due to moment forces (load being more than capacity). There of course are other means of failure in beams but from what you're describing I don't believe there's risk of that.

The first of those two, compression - I have seen. It is not as common and typically happens when there's water or prolonged humidity on a wooden beam. Or, if you have other acute drivers of weakening the wood - for instance termite damage etc. We had that exact thing happen with numerous joists in a vacant house that sat for years in a house with roof failure. All the water getting down in the basement caused lots of humidity, so you'd have 'notches' form in the tops of the joists where the loads were heavy and would 'push' down on the joists.

Picture in this case for moment forces a super long 2x4 (say 20') where you apply a large force to the end of the board, when its supported/stuck on a fulcrum. At some point, the combination of length and force will cause the board to snap, somewhere along its length. This is the primary failure point and design criteria for a beam.

The good news is that one way to defend against any risk of moment forces failure would simply be to add additional posts interspersed to your existing system. There would still be some costs there but to me this is probably the most elegant solution based on what you're describing, if you choose to do anything. A possible/proposed solution might to be supplement the existing posts where there are issues, and add new posts where there may be any risk of moment forces causing failure.

As long as there's not acute damage due to water, termites, etc of your joists I think this would be a reasonable approach to at least explore.

Most jurisdictions do look for opportunities to ensure that when a contractor touches something they replace MOST or ALL of the system. Examples of this include when a plumbing inspector sees any cast iron left above the main stack they will make a plumber replace all that cast with PVC and possibly dig into the venting, etc. Same thing applies with electrical - service upgrades usually come along with upgrading the entire system to get a 3W system in a house... Costs add up quick.

However from my experience structural and foundation systems are a different animal in this regard and I don't think it's reasonable or defensible for a regulatory jurisdiction to take this stance. My first thought here would be to supplement any acute signs of wear/possible risk/failure - for instance - sister next to existing post that showed signs of rot/etc at bottom with a post that provides adequate capacity.

Removing and replacing to me does nothing positive. Just dig a footer and put something next to it to supplement. Perfectly reasonable and doesn't sacrifice anything....

You as an owner can look up capacity charts of various post sizes. What an engineer does is not rocket science, it just happens to be really boring and analytical to a lot of people sometimes :)

Estimate the loads of the part of the house that this post is support (I'm talking EVERYTHING, all the sub floor, walls, sheetrock or plaster, everything above it) and see how the capacity of that post section compares to the load.

Don't do this to act like you have authority as an engineer, however you can be armed to negotiate and push back on your engineering firm that you hired. Use the term 'value engineering' and threaten that they are over engineering and perhaps throwing one of their under-experienced younger guns at something.... I bet you'd get some movement/results there.

Most of what you paid for there was the time for someone to go out and do all that 'take off' time to lay out your house and document what was there. What you WANT to be paying for is for that elegant solution from good experience, from your engineer.

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Jared W SmithBusiness Member

Architect · Westchester County, NY · Member since 2018 · 681 posts · 476 votes

8y

@Kevin Castaneda Unless you have a design background (architect or engineer) in understanding the forces at play and appropriate codes with references, then I'd say your should go with the engineer's report recommendations. They most likely did a preliminary calcs on the property and to size of the beams. This takes the tributary areas for each beam in account. You should confirm this with them. Yes, based of my experience working with many engineers, they always have a safety factor, usually 10-25%. It takes into account this for things like contractor installation and material variables.

When dealing with the foundation companies/contractors, they are likely to tell you what they know best and it might very well work but unless they are having someone stamp it as a PE plus file it and take liability, I wouldn't trust their input.

Personally if you renovate a 1920s home and discount the foundation work, it's negates the niceties on main floors. correcting foundation in future could disrupt the finishes. A good home inspector is going to for sure check foundation and make necessary comments.

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Elliot Grochal

Investor · Portland, OR · Member since 2014 · 25 posts · 12 votes

8y

Hey Kevin, you put in an incredible amount of research and thought here, congrats on that! I just rehabbed a 1920 property in San Antonio that had considerable foundation issues, so it wasn't really an option for me. We ended up putting in 40 new concrete piers and about 160 LF of treated beam. We are still closing up walls, so I don't have a finished product to share with you yet. In response to your 4 questions:

Would the average person buy a 1920s house that hadn't had the foundation updated? If it's not too bad, I'm sure someone would especially in our hot market, but like Jared said it would be a shame to do a bunch of work and then run into issues down the road.
Will the home inspector get under the foundation and ask for an engineer's report? Quite likely. Though if you have a foundation company that says the foundation is in ok shape, perhaps you get a letter from them to show a potential buyer it has been looked at by a company?
If we did nothing, I'm concerned about having to perform the foundation repair on the back end and whether that would screw over the new drywall/painting, re-hung doors/windows, and bathroom tile work all just done to the home? Yes, see question 1.
How would you handle this foundation repair? Very much depends on what you intend to do with the house. Trying to sell right away? Holding and renting? Also depends how much other work you are doing to the house, and what your sold comps are. Happy to talk further if you like. Good luck!

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Jim Cummings

Residential Real Estate Broker · College Station, TX · Member since 2013 · 1k+ posts · 969 votes

8y

@Kevin Castaneda. I would suggest you speak with the Engineer to get them to revise their report. Maybe the engineer would agree with "Sistering" the beams or even some other less costly options.

Without changes to the report, you are faced with providing a Texas Seller's Disclosure Notice that essentially says you need to replace / beef up much of the Foundation. That is going to be a Red Flag for any Inspector or Buyer.

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Brian Pulaski

Flipper/Rehabber · Montgomery, NY · Member since 2016 · 2k+ posts · 1k+ votes

8y

Beams, or columns? Looks like columns? Also it reads that you needed to get a report, the report says to fix and gives you how to fix it. Unless you can get another Engineer to put on paper that no fix is necessary, it seems like you have to do something, no? It seems like you have conflicting info from foundation companies and an Engineering report. Will any of these companies who say you don't need to fix it, have their Engineer put that in a report? Have any of them done any engineering or just made assumptions?

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Foundation Overkill and Appropriate Beam Sizing

Foundation Overkill and Appropriate Beam Sizing

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