DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Building & Construction (http://www.diychatroom.com/f19/)
-   -   Flagstone patio vs. Foundation (http://www.diychatroom.com/f19/flagstone-patio-vs-foundation-22511/)

Cangirl 06-19-2008 12:32 PM

Flagstone patio vs. Foundation
 
We took out a concrete pad against our house and replaced with a large flagstone patio (mortared, not sand base).

There is a definite slope away from the house, so we're good there.

I can see that there was flashing behind the siding and between the foundation and concrete pad. Can someone tell me if this is suggested (required) with the new patio?

Relative told me just to fill in the space with mortar...

Any suggestions?

Termite 06-19-2008 02:14 PM

Can I assume that your siding is very close to the level of the patio? That would account for the flashing at the siding in some cases.

There is normally a gap of some sort between a concrete pad and a home's foundation. This is essentially an expansion joint. Your house is on footings deep beneath the surface, so it is reasonably immune to heaving in frost and sinking due to settlement of the soil. The pad, on the other hand, sits on disturbed earth and is subject to movement due to settlement and frost heave. Therefore, the gap allows the slab to float, separate of the foundation.

If your house has been there for several years, you could probably put mortar or flexible sealant in that joint with no problems at all. I'd opt for something flexible.

Hopefully there is a sand or gravel base under your flagstone patio??? If they're set directly on the dirt it wasn't built for longevity.

Cangirl 06-19-2008 06:42 PM

Can I assume that your siding is very close to the level of the patio? That would account for the flashing at the siding in some cases.

The concrete pad, where the existing flashing was originally installed, was close, yes.

There is normally a gap of some sort between a concrete pad and a home's foundation. This is essentially an expansion joint. Your house is on footings deep beneath the surface, so it is reasonably immune to heaving in frost and sinking due to settlement of the soil. The pad, on the other hand, sits on disturbed earth and is subject to movement due to settlement and frost heave. Therefore, the gap allows the slab to float, separate of the foundation.

So the flashing was there in case that slab moved... got it.

Now that there is an average 1/2 inch gap between foundation and flagstone, and about 3" from flagstone to siding, can we forgo the flashing?

If your house has been there for several years, you could probably put mortar or flexible sealant in that joint with no problems at all. I'd opt for something flexible.

House was built 10 months ago. Are you guessing something will move? We were going to fill in the gap between the foundation and flagstone with mortar, just to prevent debris, leaves from accumulating. Not good?

Hopefully there is a sand or gravel base under your flagstone patio??? If they're set directly on the dirt it wasn't built for longevity.

At least 4" of 3/4 minus base, and our flagstone suppliers, "the pros," don't seem to think we get the kind of frost heave in the Pacific NW that will create problems a gravel base can't handle.

Thanks for your help!


All times are GMT -5. The time now is 02:35 PM.