Thread: Part of garage wall will be below grade.

Hi all. I'm new to this forum. Great place to share info. I started a project where I want to install a raised paver patio. It will be slightly higher than the patio in the pic and extended out as far as the end of the garage wall (picture is of the wall). I would like to know what is the correct way to construct it being that part of the garage wall will be below grade? I heard the best material to back fill it with will be crusher run. If I have to I could ad a row of block to the existing wall in the garage but is there another way and still be to code. There will be a drainage tube an inch or so right next to the foundation but if needed it can be moved. I want to do this right the first time and don't want any chance of bugs entering the home. Also there will be a paver wall at the end of the garage wall (just to the right. Out of view) coming at you from in the picture. Will a gravel footer be enough to hold all the weight without settlement and frost problems? I live in Bear, DE. Thanks in advance. Larry.

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Larry,

A couple of rules of thumb. The siding should be about 6" above the finished grade. The finished grade for soil should slope 6" in 10 feet away from the foundation wall. You could have a lesser slope for a paved patio but it must shed water away. If you are going to have a patio that slopes away to shed water why do you need the drain? As far as footer depth try this NCDC: Climatic Data for Frost Protected Shallow Foundations - Maps you should also check with you local building official.

Hope that helps
Bruce

I'm assuming that the porch slab is the finished height? + paver? You will need to lose 2 rows of siding and will need a full flashing from below present gound level preferably into a drain system to right up under the siding. You cannot put gravel or soil against the foam. That wont work.
This still is an unconventional application but will work.

Originally Posted by wayne soper

I'm assuming that the porch slab is the finished height? + paver? You will need to lose 2 rows of siding and will need a full flashing from below present gound level preferably into a drain system to right up under the siding. You cannot put gravel or soil against the foam. That wont work.
This still is an unconventional application but will work.

Except for termites and or what ever coming up behind the flashing just as in stucco brought to the soil.

Originally Posted by wayne soper

You will need to lose 2 rows of siding and will need a full flashing from below present gound level preferably into a drain system to right up under the siding. You cannot put gravel or soil against the foam. That wont work.
This still is an unconventional application but will work.

Originally Posted by Ted Menelly

Except for termites and or what ever coming up behind the flashing just as in stucco brought to the soil.

I'm with Ted, that ain't going to work.

You will want the top of the pavers at least 4" below the bottom piece of siding after re-installing the siding all the way down to the concrete foundation wall.

You want that framed stud wall area (I am presuming there are studs behind that foam insulation) fully above the top of the pavers by that 4" stated above.

That means your pavers will be stepped down from the porch on the left, which is no problem, just build in some steps, making sure the steps are clear of that side wall.

Lawrence:

What everyone is trying to say is, if you are in an area that enforces a building code, the Construction Official should not issue you a permit for what you want to do.

You want the patio to be ABOVE the current patio; this means the wood frame for the garage will be below grade. That is unacceptable.
The only way to do what you want is to replace the garage wood frame with block or concrete at least 8 inches above the new patio grade.

Your best bet is to talk to your town construction official prior to doing any work.

Originally Posted by Darren Miller

You want the patio to be ABOVE the current patio; this means the wood frame for the garage will be below grade. That is unacceptable.

Another way to put that is like this: If you do go ahead and do as you want to do, when you sell your home and move, your buyer's home inspector will write that up, meaning that not only will you have to remove it all, but then all the framing which has been damaged will need to be replaced. In other words - you will have major repairs to the structure which would need to be made at considerable $$$$$.

The only way I can see you being able to do even close to what you want to do is to:
a) First construct a raised free-standing deck (not connected to the house, with adequate air space between the deck and the house) with pressure treated plywood on the deck sub-floor (which would normally be the deck floor).

b) Float on a lightweight concrete over the pressure treated plywood.

c) Spread and level out the sand base for the pavers.

d) Install the pavers on that sand base.

Make sure to calculate the height of everything so the tops of the pavers end up where you want them.

e) Be aware that when the wood decays, and it will over time, that you will need to tear the entire thing down and rebuild it.

Other option:

f) Constructed a masonry wall around that area, leaving space between the house and the masonry wall next to the house.

g) Place precast concrete floor slabs on the masonry wall.

h) Place the sand bed on those precast concrete floor slabs.

i) Lay the pavers on the sand bed.

That should provide a very long life 'raised paver deck', but you will be spending many $$$$$ in constructing it. And, yes, you will want it engineered so you know it is capable of handling the loads for its lifetime.

We are saying 'Do not do' what you are starting to do.

I am following that with an alternative for you 'to do', but making you aware that it will cost many more $$$$$ than you had originally planned.

Ditto what Darren said. And even if you live in an area that does not enforce a building code, taking a wood framed exterior wall (garage wall) and burying it in the ground is not something you want to do to your house. Aside from the fact that the wall is not designed to hold back the weight of the stuff you want to pile against it, it is an open invitation to moisture damage and insect infestation.

Time to go back to the drawing board. I think you need to make some fundamental choices between the material you want for your surface, whether you want a multi-level or a single-level patio, and the cost of the job to do it.

If you want pavers, you need to choose between a single-level patio (your initial plan) at high cost, and a multi-level patio (like in Jerry's post #5) at low cost.

If you want a single level paver patio, you need to choose between running it up against the house, or making it free-standing. Either option will be high cost.

Running it against the house will require you to raise the block foundation wall and rebuild the stud wall between the patio and the garage.

Making a free-standing platform to support the pavers (like in Jerry's post #7) -- that will last -- won't be cheap either, but it will be less expensive than rebuilding the garage wall. If you go the cheaper, free-standing route, you have to make sure the gap between the house and the platform is free-draining and stays clear of debris (like leaves, dirt, and sand). You have to think long-term about that -- long after the patio is built and you've forgotten about the importance of this, or the house changes ownership. This is a long-term maintenance issue, which, in my opinion, seldom gets done, even by folks with the best initial intentions to do so.

If you really want a single level patio, and you don't want to break the bank, I suggest you consider using a different material for your surface. You could build either a free-standing or attached (properly fastened and flashed at the house) wood deck in the area behind the garage. If you don't want the look of having your single level surface being partially concrete slab and partially wood decking, increase the height of the portion behind the garage enough so that you could fasten some wood sleepers to the slab, and then run your decking over the slab as well.

Other option:

f) Constructed a masonry wall around that area, leaving space between the house and the masonry wall next to the house.

g) Place precast concrete floor slabs on the masonry wall.

h) Place the sand bed on those precast concrete floor slabs.

i) Lay the pavers on the sand bed.

That should provide a very long life 'raised paver deck', but you will be spending many $$$$$ in constructing it. And, yes, you will want it engineered so you know it is capable of handling the loads for its lifetime.

We are saying 'Do not do' what you are starting to do.

I am following that with an alternative for you 'to do', but making you aware that it will cost many more $$$$$ than you had originally planned.

Jerry, I think option 2 is the best way to go. I think putting block up to the level of the patio against the garage wall and then a cap = to the paver height on the patio keeping the cap boarder all around the pavers. The drain pipe from the gutter above the garage will have to be moved. Crusher run backfill will be OK up to the patio, right? Is Tyvek and tar paper enough of a gap between the garage foundation/foam insulation wall or should I use. I think I will get the correct permits so as not to ever have a problem with code enforcement,problems later and the sale of the house. In this economy, thank God, money is not a problem at this time.

Originally Posted by Lawrence MacDonald

Crusher run backfill will be OK up to the patio, right? Is Tyvek and tar paper enough of a gap between the garage foundation/foam insulation wall or should I use.

Lawrence,

There is a step missing which you did not include in the above.

*NOTHING* should be up next to that house wall.

The two options I gave were each free standing and separated from the wall to allow for proper drainage and ventilation (see Brandon's post, post #8). That area should be at least ... 1 foot wide minimum ... which creates another set of problems (also addressed in Brandon's post) in that the space will need to be kept open, will need a guardrail to keep people from falling through, will need to make sure that the space is kept clean, that future owners do not wonder what that space is for and decide to eliminate that space, etc., there are a lot or reasons and considerations which need to be given to the width of that space and the long term effects, use (should not be used for *anything*), maintenance, and making sure that the space remains a "space".

In this economy, thank God, money is not a problem at this time.

That is a good thing, because to do either option I presented and to do them correctly will certainly make you cringe, if not change your mind, once you begin to have this structurally addressed by a structural engineer, designed, permitted, and then the actual construction.

I would encourage you *not to go with my first option* of using wood as it does not last 'for the long term' under those conditions, meaning the money would all need to be spent again to re-do it all.

I would encourage you to put in a footing, down below frost level, with a foundation wall - separated from the garage house wall by at least 1 foot (would be easier to maintain that space if you made it large enough for you to get into it and clean it, which means closer to 3 feet wide), then have the precast floor panels made, or, heck, once you have got that foundation wall away from the house, just fill the area within the block foundation walls with compacted fill, then lay the pavers on a sand base on that compacted fill. If you consider making future changes from pavers, or if you want to avoid paver settling, pour a slab on the compacted fill to the height of the existing patio, then cover everything in pavers.

That would save a lot over precast floor panels.

The critical area is: Make sure that wall of the garage is completely separate from the free standing patio/deck you construct. Remember, you do not want that space small enough that debris can accumulate in it, if debris does accumulate in it, it is only a matter of time before that wall is affected negatively and then requires rebuilding - which would not be an inexpensive undertaking.

Being one who does not count other peoples money (it is your money, which is no problem for me , or you as you stated), you will want to select the best method which protects that separation space between the house and the free standing patio/deck.