Non PT Framing on the foundation

[Dennis]

We have a local contractor who has built thousands of high end homes in a pretty unique neighborhood. Years ago I had the opportunity to work on a few of his older homes from the 80's. The floor joists were non PT and were laid onto the cinder block foundation wall and nailed into the band. No sill plate was installed. I was told it was legal as long as the wall was higher than 18" off grade.

Was this legal and if so is it still compliant?

 

[ICE]

Current California code

SECTION R317

PROTECTION OF WOOD AND WOOD BASED PRODUCTS AGAINST DECAY

R317.1 Location required.

Protection of wood and wood based products from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative-treated in accordance with AWPA U1 for the species, product, preservative and end use. Preservatives shall be listed in Section 4 of AWPA U1.

1. Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation.

2. All wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.

3. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.

4. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 1/2 inch (12.7 mm) on tops, sides and ends.

5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground or less than 2 inches (51 mm) measured vertically from concrete steps, porch slabs, patio slabs, and similar horizontal surfaces exposed to the weather.

6. Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.

7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.

#3 has me wondering. The impervious moisture barrier is where exactly? Between the slab and the dirt or between the slab and the wood? The way it reads, I would say the barrier is between the slab and the wood. That doesn't make as much sense as between the slab and dirt.

 

[DRP]

I don't have an older copy, this is from the NC Uniform Building Code '68 with ammendments through 10 Dec '85.

Section 19 Wood Construction- General

(6) Protection Against Decay and Termites:

(a) In areas subject to termite damage, the following locations shall require the use of an approved species and grade of lumber, pressure preservatively treated in accordance with the standards in para (f) or heartwood of Bald Cypress (Tidewater Red), Redwood, and Eastern Red Cedar.

1. Wood joists or the bottom of a wood structural floor when closer than 18" or wood girders when closer than 12" to exposed ground in crawl spaces or unexcavated areas located within the periphery of the building foundation.

2. All sills which rest on concrete or masonry exterior walls and are less than 8" from exposed ground.

3. The ends of wood girders entering exterior concrete or masonry walls which have clearances of less than 1/2" on to, sides, and ends.

4. Wood siding on the exterior of a building having a clearance of less than 6" from the ground.

How had it done when you went back in there? If appropriate, who was the builder, just curious I was around there then.

Out of curiousity I flipped back a few pages, Excavation; depth of excavation of trenches for walls, piers and footings shall be carried below the frost line.

 

[Dennis]

This is Farrington development in Northern Chatham County on 15/501 about 3 or miles from the orange county line. I am not sure it is appropriate to mention names but he was/is the only builder in that development. As I stated the block walls were 18" or more above grade and the non pt. pine 2x10's were just placed on the wall- no termite shield or sill plate. The band was attached to the ends and siding nailed to the band-- don't know what was behind the siding.

I work on high end homes and I had never seen anyone frame a home like that. It does sound compliant.

 

[fatboy]

It would be legit under all codes I've enforced under.

 

[Francis Vineyard]

Excuse my ignorance for asking but is an anchored sill for bracing the wall above and horizontal diaphragm for the foundation wall not always required, and if it is how can it be done without a sill plate with the framing described in the OP?

Francis

 

[DRP]

Francis, look at fig 404.1.5(1). The straps bypass the sill and grab the rim. The sill/rim connection is pretty lousy on most houses, think of the post storm pictures of sills still bolted to foundations. A Simpson hold down bolted to the foundation and rim would do it as well.

 

[Francis Vineyard]

DRP, Apparently today it would be an approved engineered design without the sill and connector shown in fig 404.1.5(1) All this is mute depending on what the code was at the time of construction.

What's the purpose of the sill plate in the figure?

Shear is what we have more of a problem with here, but not from wind or seismic; vehicles hitting the structures.

Francis

 

[Architect1281]

“It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.”

Mark Twain

 

[DRP]

DRP, Apparently today it would be an approved engineered design without the sill and connector shown in fig 404.1.5(1) All this is mute depending on what the code was at the time of construction.What's the purpose of the sill plate in the figure?

Shear is what we have more of a problem with here, but not from wind or seismic; vehicles hitting the structures.

Francis

Let's step back further... what's the purpose of a sill?

 

[Dennis]

Let's step back further... what's the purpose of a sill?

I always thought the primary purpose is that of a termite shield but it also keeps non pressure treated wood from coming in contact with concrete. No?

 

[Francis Vineyard]

Let's step back further... what's the purpose of a sill?

As I see it the strapping over the double rim joist are used in place of anchoring the sill to the foundation wall, what I'm guessing if the wall is not thick enough for the floor joist to have 3" of bearing on masonry then the sill can give compliance with 1½" on wood. I supposed the option would to use joist hangers instead. But if a builder says the sill in this instance is not necessary as shown in the figure; what purpose does it serve that it's not necessary?

I always thought the primary purpose is that of a termite shield but it also keeps non pressure treated wood from coming in contact with concrete. No?

Dennis as an option if the sill is pressure treated or of naturally resistant wood can double duty as a termite barrier. DRP along with majority of other participants knows more about this stuff and may give us a better answer.

 

[DRP]

Actually I had never given it a thought, I just always put down a sill. It does allow the anchor bolt location to float more. I could put down a metal termite shield with or without one. It does give a chance to level an uneven foundation and provides a plane if there are irregularities, the rims really do that too. Back when a sill was an 8x8 or larger it was a beam that spanned across a loose and very irregular foundation or piers, I can see a definite reason for it. I think your contractor just left out a vestigial member... but I think I'll keep using one.

A termite shield is really not really a barrier nor is a piece of wood. If they don'y care for something they will tunnel over its' surface. The purpose of a shield is to make subterranian termites come out to the surface and show a tunnel between the ground and the untreated wood. Using a decay resistant species is not a guarantee that termites won't tunnel through it. They don't have the jaws to tackle black locust but they can hold their noses long enough to make it through some treated.

Francis, on the pier and curtain wall with a minimal brick curtain wall I think you're right, the bearing would need to be on wood to provide adequate code joist bearing length. The wood does need to be bearing though. Getting further off track but one company wanted to avoid using joist hangers on porches. They use a treated rim, slid the sill outboard 1-1/2" and used that as a ledger to set the porch joists on. tension perp, that was asking to snap off,