Best fill material

[92U 3406]

I need to backfill around a house foundation as there's a negative grade towards the foundation. Just wondering what would be the best fill material to use in this situation? No topsoil will be placed on top.

 

[Shimmy1]

Drain tile? I would use Class 5 anyway.

 

[92U 3406]

I'll be honest, that was completely Greek to me. I've got zero experience with dirt work.

 

[Shimmy1]

Is there drain tile around the footings?

Even if there is, I'd still use crushed road gravel. It'll pack in tight and shed the water away from the structure. Added bonus, if you have unstable soil around there, the gravel stays solid.

 

[92U 3406]

That I don't know. Maybe backfill wasn't the right word. From what I can tell someone laid down some topsoil for the lawn years ago but never built up the grade under the deck on the house when they did it. I'm doing some work on the deck and figured it might not be a bad idea to build up the grade so it slopes away from the house, rather than towards it.

 

[Delmer]

The usual way that happens is the fill around the foundation settles, then the water pools and dissolves more soil as time goes on. In any case, I'd want a heavy clay subsoil to keep as much water from getting through as possible. Coarse crushed rock or sand would just allow the water to keep running down the foundation wall. It doesn't have to be pure clay, something like 75% sand and 25% clay can still be a very tight and impenetrable soil. Crushed rock with enough fines would work also, limestone screenings would pack nicely and stay better here.

 

[cuttin edge]

Are you in Ontario, or farther west? How much higher were you planning to build up the grade? If you are doing it by hand, you want material that is not too coarse so you can work it. For under a deck, I would go with some type of crushed gravel. Not clear stone, but something that will compact. For around the house, if it's grass, and you are not building up real high, I would just use top soil. I don't like topsoil under a deck because it stays damp, smells, and helps rot the wood.

 

[Jimothy]

If it’s just surface water your dealing with you can use French drain either with a pipe or just washed or clear gravel. Something that allows water to flow throw it and trench it away from the house. I know our house has a negative slope towards it and we chose to put 2 swales in the area just to lead water away from house. But all of this depends on situations we have spent thousands of dollars trying to fix water problems for buildings but always look for the simplest solution before you dig up the entire planet.

 

[CM1995]

Any pics 92U?

Also have no idea what Class 5 backfill is either. Crushed stone terms vary widely across the continent.

 

[92U 3406]

Are you in Ontario, or farther west? How much higher were you planning to build up the grade? If you are doing it by hand, you want material that is not too coarse so you can work it. For under a deck, I would go with some type of crushed gravel. Not clear stone, but something that will compact. For around the house, if it's grass, and you are not building up real high, I would just use top soil. I don't like topsoil under a deck because it stays damp, smells, and helps rot the wood.

Out in the prairies. Don't really have any issues with water getting to the foundation, the deck does a decent job of keeping most of it away. At the worst spot I'll be building it up about 10-12 inches at most. Right now there's just fine sand under there.

 

[92U 3406]

Any pics 92U?

Also have no idea what Class 5 backfill is either. Crushed stone terms vary widely across the continent.

Not off hand. I'll try to grab some tomorrow if I remember.

 

[Tinkerer]

I would use sand to create a slope away from the foundation.
Then cover it with a heavy sheet of poly plastic sheeting.
Anchor that down with some course stone. It will direct the water away from the building and block weed growth.
That worked for me when I built my deck, but I hated the mosquitoes and wasps that liked the underside of it.
I eventually removed the wood deck and installed an elevated brick patio.

 

[Welder Dave]

Even packed clay would work. If it was mixed with a little black dirt, sand or other type of soil wouldn't hurt. The landscape fabric with some washed rock or even crushed concrete on top would prevent weeds and maybe keep critters out too. When I did rough grading for homes it was usually just clay and once approved by the lot grading inspector the topsoil could be put on. Didn't need the topsoil under a deck but was best to slope under the deck so water wouldn't run under from the sides.

 

[Acoals]

Find out what is available. As you travel around the country every region has different materials, you pretty much use what there is to use. Call the nearest sand and gravel or excavating outfit and ask them what they would recommend for what you want to do.

As an example, around my area I would just use what we call "pit run", which is basically going to be sandy soil. Clay might be better, but there really isn't much of that around here, and I am not going to drive 40 miles to find something perfect.

 

[Chris H PM]

What kind of soil are you working with up there? generally using a non-woven fabric with 2 1/2" washed/clean round rock with a a 4" perforated pipe will do the trick, i would 90* the perf pipe out into the yards to a small "infiltration" trench, 20 feet long is usually plenty, lay the fabric in the bottom pipe and drain on top. and backfill the top 6-12" inches, you'll want 0-1 degrees in your slope to shed the water away from your foundation.

 

[CM1995]

What kind of soil are you working with up there? generally using a non-woven fabric with 2 1/2" washed/clean round rock with a a 4" perforated pipe will do the trick, i would 90* the perf pipe out into the yards to a small "infiltration" trench, 20 feet long is usually plenty, lay the fabric in the bottom pipe and drain on top. and backfill the top 6-12" inches, you'll want 0-1 degrees in your slope to shed the water away from your foundation.

Welcome to the Forums Chris! Glad to have you.

An infiltration ditch may work in sandy soils however here in the southeast that won't work due to the heavy clay we have. Wick or french drains here must have a discharge point or it's just a soggy mess.

YMMV

 

[PeterG]

Without seeing images, it's hard to know what you got and what you need. In general I would add native fill against the house but no higher than 6" below the siding and have the slope min of 2 percent away from the house for a min of clearing the roof overhang or preferably more like several feet. May have to use an excavator if you can't add fill and need to dig down. In addition I would add an inch or so of washed rock on top of the fill, and I would have gutter drains not to drain out to open right next to the house. You can put permeable cloth under the rock, but it won't do much. Don't put plastic down, and I don't like clay. You can make sure the footing drains work, and even add a french drains / Curtain drain around the house. Regarding the french drain, typically dig a trench not more than two feet deep and one foot wide, and line it with permeable cloth. Use 4" triple white perforated pipe found at a big box hardware store. Drain out to open using solid pipe or to a big Dispersion hole. For just under and around the deck, just some local clear/washed round or angular gravel with no fines/minus.

 

[HarleyHappy]

My new house, I did hardscaping wherever there were no gutters.
Along with a curtain drain, before I put the 1 1/2 hard scape sone, I put in 6” of topsoil and then fabric so wife could put Hostas every 4‘.
under the deck, I put pea stone so it wouldn’t attract misquotes and be easy to take care of. All of it drains away from house.
Less maintenance and looks good. Bout 2k in granite pavers all around.

 

[cuttin edge]

I think we are over complicating this. Right off the bat, I didn't read his full post, and suggested topsoil which he was not planning on using. He has stated that the water does not get to the foundation, and that he just wants to eliminate a low spot under the deck. Just use whatever is cheap and available, and if you are doing it all by hand, preferably something that is easy to shovel. I'm lead to understand there is a lot of clay out west. That would do. Stone would just hide the low spot, and hold any water without a drain to take it away. I'm a fan of crushed gravel because I use it every day, and we have lots around, it compacts and sheds water.

 

[92U 3406]

I think we are over complicating this. Right off the bat, I didn't read his full post, and suggested topsoil which he was not planning on using. He has stated that the water does not get to the foundation, and that he just wants to eliminate a low spot under the deck. Just use whatever is cheap and available, and if you are doing it all by hand, preferably something that is easy to shovel. I'm lead to understand there is a lot of clay out west. That would do. Stone would just hide the low spot, and hold any water without a drain to take it away. I'm a fan of crushed gravel because I use it every day, and we have lots around, it compacts and sheds water.

Exactly what I'm working with. Right now it looks like just sand under there. Even on the worst rain storms it doesn't get much more than damp under there.