Permanent ground “foundation”

Powak · March 2021

I’ve got my large egg in it’s nest in my yard. I’ve live in New England and got no intentions of putting it on my deck or a installing a concrete slab but am looking for another solution to keep it from A) sinking into the ground and

moving with the frost yearly. I was wondering if anyone has a recipe of how much crushed rock, sand and how deep to go into the ground for make a solid spot for the egg to sit year round?

alaskanassasin · March 2021

You can start by saving your RockWoods!

alaskanassasin · March 2021

I would go about 6”, pack in 4” of stone, a bag of sand or two to level then 4 16” square pavers

PigBeanUs · March 2021

alaskanassasin said:

I would go about 6”, pack in 4” of stone, a bag of sand or two to level then 4 16” square pavers

This

in new england you either defeat frost by going down three or four feet, or you do an end-around by keeping the water from getting under it.

You don’t want to put in a four foot foundation for a grill. So ride it out on top

The crushed rock and sand will be perfect support for the pavers.

fishlessman · March 2021

mine sits on the ground in maine in the mud, a 15 inch circle of stainless plate and the three feet. but the above post would be better with a nest

Gulfcoastguy · March 2021

Be sure to rent a vibratory tamper and keep the crushed limestone wet while packing it. We did all of the brick paver walk ways at a public rest area that way.

northGAcock · March 2021

Hardscaping bricks are easy to install. If you did not want to lay a pad with them, i would think you could at a minimum put one under each wheel. You will want a hard packed base with maybe a little quick set under it to firm it up.

Skiddymarker · March 2021

When living in eastern Ontario, my BBQ (not an egg) sat on four 2'X2' patio stones. Threw a bag of kids play sand under them to level and all was good for at least a couple of years. When the frost heaved one or two, I rolled the grill onto the lawn and levelled with some more sand. Easy and worked just fine.

Kayak · March 2021

I bought something at, I think, HD, that was a plastic pad that went under pavers. I put a PT frame on the ground and laid the pad inside that. Then 12x18 pavers in a bricklaid pattern. It will 'float' on the surface, and frost won't move it. I did put down gravel under it.

HeavyG · March 2021

A sheet of ground contact rated plywood - $60.

Lay concrete stepping stones on top - 12 of 12 in. x 12 in. x 1.5 in. Pewter Square Concrete Step Stone @ $1.68ea

For less than a Benjamin you have a surface that should rise/fall evenly if there is any heaving action.

caliking · March 2021

All I have to add to this is that Lowes has 24" x 24" pavers around here, but HD doesn't.

Powak · March 2021

HeavyG said:

A sheet of ground contact rated plywood - $60.
Lay concrete stepping stones on top - 12 of 12 in. x 12 in. x 1.5 in. Pewter Square Concrete Step Stone @ $1.68ea
For less than a Benjamin you have a surface that should rise/fall evenly if there is any heaving action.

Man that sounds good too. Do you cover the length of the plywood with the stones or cut it down to 4x4’ size and double stack the stones?

PigBeanUs · March 2021

Keep in mind that even ground-contact rated pressure treated wood shouldn’t be (wait for it) in direct contact with the ground (or even with concrete). Needs a barrier. Polyethylene sheet etc. (bc: otherwise the PT can wick out of the wood leaving you with crappy pine in direct contact with the ground. This is also why you are supposed to paint or stain the stuff after the outer surface dries, when it is exposed, like a porch).

I would stay away from plywood for a couple reasons anyway.

Any heaving under any one spot will telegraph across the whole area. With brick or pavers, it’s localized and easier to fix. Better to take up one paver and tamp down the stone and sand (or fill it), than to have to take off all pavers from the 4x4 or 4x8 area in order to lift the plywood

There’s also potential for sliding. Brick or pavers on wood?

Water. The whole idea behind paving stones on sand (or stone dust) and further on gravel and crushed rock is that rain goes right through. On plywood it will get between the joints and sit between the pavers. When it freezes, they will push apart

there’s a reason no one uses plywood under paving stones for any long term landscaping project in the northeast.

There is no need to improvise and reinvent

dig down 8” or more. Crushed rock. Stone dust or gravel on that. Pavers tamped down

Depending on how permanent you expect this to be, you may want edging to hold it in place.

There’s always movement, but you can minimize it with better prep and better edging alternatives

Kayak · March 2021

I've put in a lot of 'dry-laid' walk and patio, it's a lot of work. For my Egg platform, I bought this:

PAVERBASE 20.04 in. x 36 in. Black Brock Paver Base Panel-PVB5B - The Home Depot

I would never use a sheet of plywood as a base.

Mark_B_Good · March 2021

I've got mine on dirt ground, but I dug 4" deep, filled with about 3.5" lime stone screen, leveled, and put in large 16" x 24" patio stones (about 2" thick) to form a deck. The XL egg sits in the Acacia table ... nothing moved over this winter. The trick I guess is to have enough screen under the pavers that water drains nicely.

rekameohs · March 2021

How 'bout an HVAC unit mounting pad?

HeavyG · March 2021

PigBeanUs said:

Keep in mind that even ground-contact rated pressure treated wood shouldn’t be (wait for it) in direct contact with the ground (or even with concrete). Needs a barrier. Polyethylene sheet etc. (bc: otherwise the PT can wick out of the wood leaving you with crappy pine in direct contact with the ground. This is also why you are supposed to paint or stain the stuff after the outer surface dries, when it is exposed, like a porch).

I would stay away from plywood for a couple reasons anyway.

Any heaving under any one spot will telegraph across the whole area. With brick or pavers, it’s localized and easier to fix. Better to take up one paver and tamp down the stone and sand (or fill it), than to have to take off all pavers from the 4x4 or 4x8 area in order to lift the plywood

There’s also potential for sliding. Brick or pavers on wood?

Water. The whole idea behind paving stones on sand (or stone dust) and further on gravel and crushed rock is that rain goes right through. On plywood it will get between the joints and sit between the pavers. When it freezes, they will push apart

there’s a reason no one uses plywood under paving stones for any long term landscaping project in the northeast.

There is no need to improvise and reinvent

dig down 8” or more. Crushed rock. Stone dust or gravel on that. Pavers tamped down

Depending on how permanent you expect this to be, you may want edging to hold it in place.

There’s always movement, but you can minimize it with better prep and better edging alternatives

When used as part of a permanent wood foundation the plywood definitely would need to be protected by a poly barrier. When used as a "base" for a short term project (2 years? 5 years? 10 years?) ground rated contact plywood will be just fine sans plastic.

Those foot square concrete "pavers" probably aren't going to slide around. If that is a concern then use the 16" (or 18" or 24" which are the ones I most often use) square versions. They're heavier and the coefficient of friction between the rough concrete surface and the wood will prevent them from sliding around.

Possibly fair point about the water freezing and spreading the stones apart but I can't see that the spaces between the concrete stones would allow the retention of but the thinnest film of water.

I live in coastal Virginia and frost heave is just something I know from textbooks so I'll certainly defer to the wisdom/experience of folks that actually live in and have to deal with climes where frost heave is a real thing.

What I do know is that I have used ground rated contact ply for a base for a couple of projects over the years. Most were short term (5 years-ish) but a couple are 20+ years old and doing just fine. My soil is mostly gummy gray clay and when I placed an 8 foot long metal firewood rack in order to keep it from eventually just sinking into the ground I used a half sheet of treated ply placed right on the soil and covered with concrete stones. Hasn't posed any problems in 20+ years.

If someone knows that they have found THE SPOT for their grill then it probably is worth spending the time, effort, and $$ to do a more suitable permanent solution. If someone isn't yet certain they know the permanent place for their grill and is thinking they might want to try a few spots over the next few years then the ply/pavers is something that can be relocated/re-assembled in less than half an hour.

HeavyG · March 2021

Powak said:

HeavyG said:

A sheet of ground contact rated plywood - $60.
Lay concrete stepping stones on top - 12 of 12 in. x 12 in. x 1.5 in. Pewter Square Concrete Step Stone @ $1.68ea
For less than a Benjamin you have a surface that should rise/fall evenly if there is any heaving action.

Man that sounds good too. Do you cover the length of the plywood with the stones or cut it down to 4x4’ size and double stack the stones?

I knew I rushed thru my reply. I meant to say 16 of the foot square stones (got 12x12 stuck in my head).

For just a pad for one Egg just using half the sheet is large enough. Save the other half for later use or just go ahead and stack the two half sheets. I've done that in the past and when I've done that I put in a few screws to keep the ply sheets from sliding around each other while getting things in place.

Good luck with your project. See my reply to PigBean - I have zero practical experience with frost heave so take that into account when deciding what to build.

PigBeanUs · March 2021

The guy can do what he wants.

He’s in New England, as he mentioned.

So water between the joints is a concern with freezing.

fishlessman · March 2021

all i know is i have rocks, sand and patio blocks in the yard and mine just sits in the mud

Powak · March 2021

alaskanassasin said:

I would go about 6”, pack in 4” of stone, a bag of sand or two to level then 4 16” square pavers

This sounds like the way to go up here. Think I’m going to do this.

Kayak · March 2021

Here's mine from 2019. That's an XL:

Image: https://us.v-cdn.net/5017260/uploads/editor/56/vy1nwsio81nv.jpg

HeavyG · March 2021

PigBeanUs said:

...

So water between the joints is a concern with freezing.

Potentially, yes. Pragmatically (in this scenario), maybe not so much.

Mark_B_Good · March 2021

PigBeanUs said:

The guy can do what he wants.

He’s in New England, as he mentioned.

So water between the joints is a concern with freezing.

Ehhh. I have a concrete stone base (8" x 4" stones) on my pizza oven outside, held together with only PL. Hasn't moved in 4 years, at all. I think part of the trick is to leave the joints open, so the water drains ... even if it freezes, as long as it has a way to expand out of the joint, it will do that before it starts moving the stones.

Permanent ground “foundation”

Comments

Categories