Residential Construction circa 1856

[DaveVikingPE]

I'm working on a project at a distance...

Problem: can a two-storey house built in 1856 handle 80 psf floor loads?

What I have: a bunch of very hard-to-read microfiche apperture cards - no framing plans on 'em but they do show romm dimensions and the like, very little time, no access to the building (I can't get a look at the flooring system, either!), a lot of frustration.

My task is to come up with a best guess of what the floor can take - so I need to know what kind of floor joists would typically be used in constrcuting a house in a suburban US area. So far web searches have yielded not enough.

If anyone knows of good books or web resources please let me know.

Thanks in advance!

 

[IRstuff]

Not sure if this helps or just confuses things.

My parents' house was built in 1926 in San Francisco. Stud and joist spacings seem comparable to current building practice. What is primarily different from current construction is that the smallest dimension wood used was 4x4, for both studs and joists. TTFN

 

[dicksewerrat]

Most of the framing members were 'full cut' lumber. I learned this by helping tear apart and salvage a couple old , 1880's buildings. The nails were larger also. And they seem to use a lot of them. This said 80psf is still a little high for most framing. A full 2 x 10 has an Ixx of 166 and Sxx of 33. Don't forget the dead load plus the live load.

 

[dik]

The only way to determine the strength is to 'get in' and measure it or load test (hope it's strong enough <G>). It's a matter of discreetly drilling to determine the width and using a small rod (wire) to determine the depth sometimes. My experience with old framing is that it's either 'really good' or 'really bad'; I've almost never found things to be just right. You also have to be very careful about some of the neat details and framing. I've encountered trimmers around stair openings that have been counstructed using mortise and tenon construction (reducing the required strength to the point it was inadequate).

Having measured the sizes, you may have to obtain a sample or two to do some testing. Lumber, in the good old days, can be remarkably strong and with a little judgement useable strengths can be determined. Strength of early lumber is due to the seasoning, the closeness of the annual rings, the absence of knots and other defects, the straightness of grain , etc. Also have to check areas where water may have entered the framing; dry-rot (misnomer) can significantly weaken lumber.

My brothers and I build my parents home using salvaged DougFir joists that were about 100 years old. Lots of 20'-24' 2x12's, nearly all perfectly straight grain and very few knots. Old square iron nails were used... the joists were so well seasoned that you couldn't pull nails or drive them in.

Because of the age of the home, you may want to reassess the loading. 80 psf is a pretty substantial load, in particular over any sort of area; it's like loading the entire floor with full beer cases stacked 3 deep... <G>

 

[PEinc]

It's very important to see the condition of the wood framing. In 147 years, it is very possible that wood members could have been cut or notched during utility installations. It is common for people to cut significantly into wood joists in order to run a new pipe, duct, or wire. I've also seen 16&quot; x 16&quot; timber beams totally rotted through at the bearing wall while the building still stands.

dicksewerrat is right about the 2&quot;(full) x 10&quot; joist sizes but sometimes their spacing is also greater than 16 inches.

I'm not sure how you can give anyone a floor load guestimate if you haven't seen the building. I think you would be sticking your neck out pretty far!

 

[DaveVikingPE]

Thanks, everyone.

PEinc, you are absolutely right! ...and I caveat-ed my guess/analysis with &quot;...I still NEED to see the floors!&quot;

And thus, the powers that be have listened to me and I'll make a site visit next week.

anyway, in my web searches, I found this site,

http://www.housemouse.net/,

that offers reprints of books like &quot;AMERICAN DOMESTIC ARCHITECTURE - Originally published in New York, 1889, by William Comstock. Illustrated.
New Printing, 2001, Merrymeeting Archives. Spiral-bound book, 11&quot; x 8½&quot;.&quot; for the princely sum of $33.