PWF - what type of wood is used?

[Devin Bolduc]

As a point of possible interest, in very old structures in the northeast, maybe elsewhere too, you may find ground contact post and timbers hewn out of black locust. It is the densest, strongest wood in northern New England and has a natural resistance to WDO. It was used as sills and very often as fence posts. I know of one particular fence post that still is functioning which was old 50 years ago so probably 100 or so now. 50 years is what was considered working span for black locust posts of 6-8". Here the decay range for posts is ground surface down to around 16" generally so posts could be reused. Being very precious and hard to cut and work for the old timers, it was used for long term applications. It also has vicious thorns. It makes very good firewood although tricky to get burning for the novice. Black locust was taken out west and raised for timbers in mine shafts due to the properties of the species. It was sometimes used for tool handles but hornbeam was more popular due to much smaller tree diameter and similar strength.

[Kenton H. Shepard, CMI]

Originally Posted by thowell

I'm due to inspect a wooden home foundation this week. Any tips on what to look for beside detailed moisture testing and bowing.

I read some more and found what I was looking for. Should have read more first

Disclaim! Disclaim! Disclaim!
How're you going to know if it's rotted 6 feet down?

What did you find when you found what you were looking for?

[David E. Helm]

Hi Kenton, just a note to mention that there is no such tree as hem-fir. The actual tree is Western Hemlock that supposedly has the same structural characteristics as Douglas Fir. Hemlock is the structural pressure treated lumber of choice because the treatment goes deep into the wood. Douglas Fir pretty much rejects the treatment. In PT plywood made on the west coast it is all hemlock.

[Kenton H. Shepard, CMI]

You're right David, it is Western Hemlock, but Hem-Fir was what the stamp on the pressure treated lumber said when I was in the trades in CA and CO.

[David E. Helm]

Yeah Kenton, the stamp does say hem-fir. That signifies that the hemlock has the same strength characteristics as fir. Once was at the lumber yard buying some studs. The lady at the contractor counter was talking about hem-fir trees. I didn't have the heart to tell her the real story.

[Mitch A. Harris]

We installed two wood foundations in 1978, we were very careful to follow engineering documents because it looked like the foundation would probably fail, and we didn't want any exposure. The foundations set directly on pea gravel, and the basement floor poured over the sole plate and into the stud spaces. The basement was designed to only backfill about 5', with 3' of foundation wall above grade. These foundations were so easy to install, fast to install, and ready to insulate and Sheetrock the outside basement walls that I thought that they might really catch on. They didn't, but I did look at the two houses a couple years ago, and asked the owners if they had encountered any moisture problems, or structural problems, and they said no. That's 30 years, I'm still not sure how they survived so well but I might consider doing another wood frame (PWF) since the other two did so well. If I remember correctly they were pressure treated yellow pine.

[Kenton H. Shepard, CMI]

Hutchinon's pretty dry compared to many parts of the US, Mitch. And I'm thinking that "correctly installed" is the exception rather than the rule.

All it takes is for a home to be sold, the new owners want to put in flower beds next to the home, install an irrigation system and the foundation's days are numbered.

Too many bad contractors, too many opportunities for failures that can destroy the whole foundation.