Foundation Overkill and Appropriate Beam Sizing

[Kevin Castaneda]

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:

1. Would the average person buy a 1920s house that hadn't had the foundation updated?
2. Will the home inspector get under the foundation and ask for an engineer's report? 
3. 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?
4. 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 girders
• R602.7(1) - Girder Spans and Header Spans for Exterior Bearing Walls
• R602.7(2) - Girder Spans and Header Spans for Interior Bearing Walls