Floor joists set into concrete


My sister is having a house built in Calgary, Alberta. She wanted me to go by to see if anything was wrong. Since I am new to home inspecting (no license yet, process of getting peer review done) I had a question about the picture with floor joists set into concrete that is not PT or no barrier between the two. I was told wood and concrete should not make contact unless PT or barrier in between. Does anyone know in Alberta if this is right?








Pressure treated lumber is used to hand siding on the form. This is no where near the ground so it is just fine. Best person to ask about the regs in Alberta would be Greg.

Alberta or not, wood should NEVER come in contact with concrete without protection… either PT or a barrier.

You are correct… the CMI is not!

Alberta or not, wood should NEVER come in contact with concrete without protection… either PT or a barrier.

You are correct… the CMI is not!

That’s not exactly what the code says (IRC). I’ll post it next.

Jeffery, you’ll see that untreated wood can be in contact with concrete. See Item 2.


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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

Code Commentary:
This section addresses the need for minimum protection
against decay damage for wood members located
in certain locations.

For those portions of a wood-framed structure that
are subject to damage by decay, the code mandates
that the lumber be pressure-preservative treated or be
naturally durable wood, or be of a species of wood
having a natural resistance to decay. Naturally durable
wood by definition is the heartwood of decay-resistant
redwood, cedars, black locust and black walnut.

Item 1: Crawl spaces and unexcavated areas under
a building usually contain moisture-laden air. These
spaces must be ventilated in accordance with Section
R408 to remove as much moisture as possible before
it causes decay. Wood placed a minimum specified
distance above grade in unexcavated under-floor areas
or crawl spaces, as shown in Commentary Figure
R317.1(1), need not be either preservative-treated
wood or wood that is naturally decay-resistant durable
wood. These clearances below floor joists and beams
are deemed to be the minimum necessary to allow adequate
circulation and removal of moisture from the air
and from the wood framing members. Such clearances
apply within the exterior wall line of the building

Item 2: Foundation walls will absorb moisture from
the ground and by capillary action move it to framing
members that are in contact with the foundation. Unless
a minimum clearance of 8 inches (203 mm) is
maintained from the finished grade to wood sills resting
on concrete or masonry exterior foundation walls,
decay-resistant or preservative-treated wood, as
shown in Commentary Figure R317.1(2), must be
used. The 8-inch (203 mm) clearance specified in this
section has been determined to be large enough to
prevent wetting of wood framing members under most

Item 3: Concrete and masonry slabs that are in direct
contact with the earth are very susceptible to
moisture because of absorption of ground water. This
can occur on interior slabs, as well as at the perimeter.
In the case of wood sills or sleepers placed on concrete
or masonry slabs, decay-resistant wood or pressure-
treated wood is required where the slabs are in
direct contact with the ground, as illustrated in Commentary
Figure R317.1(3). Concrete that is fully separated
from the ground by a vapor barrier is not in direct
contact with earth.

Item 4: A minimum 1/2-inch (12.7 mm) clearance
along the top, sides and ends of wood members projecting
into exterior masonry or concrete walls must be
maintained, as illustrated in Commentary Figure
R317.1(4), unless the wood is treated or is of a species
that is naturally decay resistant.

Item 5: Experience has shown that wood siding may
extend below the sill plate to within 6 inches (152 mm)
of the earth without decaying. Commentary Figure
R317.1(5) shows the required minimum 6-inch (152
mm) clearance from the ground for wood siding,
sheathing and wall framing on the exterior of a building.
It should not be in direct contact with the foundation
wall. If the sheathing is located over a concrete
step or slab, the clearance may be reduced to 2 inches
(51 mm) minimum.

Item 6: Concrete or masonry slabs that serve as
roofs or floor systems that are exposed to the weather
are very susceptible to moisture from rain or snow. If
these slabs are supported by wood, the wood must be
decay resistant or must be separated from the slabs by
vapor barriers so there is not direct contact. This is
similar to Item 3.

Item 7: When a basement area is finished, a com-
mon practice is to provide wood furring strips on top of
the concrete or masonry walls for attachment of finishes.
These furring strips must either be of decay-resistant
material or must be separated from the wall by
a vapor barrier. This will prevent the moisture from
moving through the walls and rotting the furring strips,
and even possibly transferring the moisture to the inside
finish materials.

Here’s the applicable code for this situation.

R317.1.2 Ground contact. All wood in contact with the
ground, embedded in concrete in direct contact with the ground
or embedded in concrete exposed to the weather that supports
permanent structures intended for human occupancy shall be
approved pressure-preservative-treated wood suitable for
ground contact use
, except untreated wood may be used where
entirely below groundwater level or continuously submerged
in fresh water.
Code Commentary:*
Wood members that are designed to be in contact with
the ground and wood that is embedded in concrete in di-
rect contact with the ground, or embedded in concrete
exposed to the weather must be suitable for ground contact
use. This provision applies to all wood members that
support permanent structures designed for human occupancy.
Untreated wood is permitted only where the wood
members will be located below the ground water level or
where the members are continuously submerged in
fresh water because fungus that decays wood and termites
cannot survive in a water-only environment with no
oxygen (see Commentary Figure R317.1.2).

Since when do I/we care what the code is?

Two words… best practices.

When you move to an area with arctic cold temps, blistering hot & humid days and nights, deep snow, torrential rainstorms, basement foundations, and deal with those conditions on a daily basis… let’s see how quick you change your stance!

I adamantly stand firm on my position!

Btw… who wants to bet the finish grade is less than 8 inches to the untreated wood? :wink:

Jerrod, I can’t tell if that wood is treated or not, but it doesn’t look like it. Note that the wood must be rated for ground contact in this case (if you use the IRC up there).

thanks Jeff, I was kinda thinking same thing about the finish grade. Other thing is we get -30 to +30 degree Celsius with an average of 4 feet of snow/year. Anyone know where to look for Alberta building codes?

thanks Joe, you are correct the wood is not treated. The wood with the gas red line on it is treated, but none of the other wood you see is.

Im trying to see if we use the IRC or the building codes but am having trouble finding them

possibly your local library


Greg will have them.

Then it will rot very SOON.

AWPA use category system:


Search for “ground contact”

Okay… what happened? Did I miss something dealing with the jerk on the other thread?:shock:

Talk about flip-flops!

You said “*wood should **NEVER *come in contact with concrete without protection”.

I simply said that the code does allow it IF the concrete is not embedded in concrete and IF the concrete was > 8" above grade.

You can call out untreated wood in contact with a concrete masonry wall 10’ tall as a defect if you want, but there is nothing to support your position (at least in the IRC).

The Alberta building code does allow untreated wood to be in contact with concrete as long as the floor joists are at least 8"(200mm) agove grade. I am not a fan and would not do it in my home but it is done every day here. Once you start into home inspection you will see it all the time.
We do not use the IRC even though alot of the code requirements are the same. We use the Alberta building code or the NBC. NBC is bare minimum code requirements. The ABC is better as alot of the codes are different and factor in our weather, moisture…
Hope this helps

awesome, thanks everyone for your help and the quick responses. :smiley:

Jeffrey what did i miss?..was it a good flip out from a jerk? I think its so funny how one guy says one thing and another say he or she is wrong. I personally verify my facts with my teacher and mentor and books but am STILL told I am wrong … There really should be a national SOP and everybody should follow it the same way - it would squish some of these flip outs - but… I still am upset I missed it, what was the link?