My home is on a slab. As originally graded when sold the
dirt level was, let's say at point X. Are there any dangers
in allowing the dirt level outside the house go a few inches
higher than X, right against the house?
Concerns: Insects, moisture, etc.
This is in the Los Angeles area.
Former slayer of dragons; practice now limited to sacred
I'd feel better having it at or below the top of the slab, and then
graded down from there. If "graded down" can't happen without having
the top of the dirt higher than the slab, I suppose it would be
preferable to have the dirt higher than to have the ground slope in
towards the building, but it's still less than ideal.
(dealing with the same issue myself... anyone want some free topsoil?)
Six to eight inches is the usual recommendation.
Typically, this is reduced over time with planting and sod.
This is Not a Good Thing.
As already noted, the top of slab should be clear of the ground.
This is usually accomplished with the distance from wood to ground.
And as already noted, sloping the soil away from the house for several
feet is critical.
If this produces a swale or channel, then that channel has to have an
Grade shold be below and away from house.
Another caution with slab flooring --watch out for termites.
Slabs have tendency to crack under a wall and not noticeable.
Termites then have way to get into wall. I was in Florida in
one subdivision every slab foor had termite problem.
Those with crawl space had none. So be on guard.
On the plans for the foundation it will show a minimum distance from
the top of slab to the grade level. 6" is what we do in CA. I would not
want it any higher do to water intrusion from the soil to the slab.
Since X is an unknown, how can X + a few inches have any meaning?
Your three main concerns are water infiltration, termites and rot. If
your house is wood framed rot due to water and termites are your
concerns. Generally you want to keep the earth at least a few inches
below the top of the concrete. The exposed concrete has another
benefit - termites have to build mud tunnels to bridge over the
concrete to get to the edible parts of your house, and the exposed
tunnels give you an early warning of termites.
If your house has masonry walls - not a brick veneer - then rot isn't
an issue and water infiltration is the biggest concern. Same idea,
keep the soil at least a few inches down and slope the soil away from
Good point. What I was suggesting was that X was whatever
the local building code required at the time of original
construction/sale, and that since then the dirt level has
gone up (at least on one side of the house) a few inches.
Thanks for your, comments/sugggestions, and those of others
who have posted in response.
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