Backfilling pole barn, need advice

[DrewStyduhar]

Whatcha think about using roofing tar instead of paint? I use tar for fence posts I set (dont paint bottom) and seems to hold up well.

The finished EXTERIOR grade is the bottom of this main skirt so figure there will be a foot or so of dirt/fill on the outside in direct contact with this second skirt.

Drew

 

[Midniteoyl]

Whatcha think about using roofing tar instead of paint? I use tar for fence posts I set (dont paint bottom) and seems to hold up well.

The finished EXTERIOR grade is the bottom of this main skirt so figure there will be a foot or so of dirt/fill on the outside in direct contact with this second skirt.

Drew

Think tar would work.

As for the outside fill, using gravel up against the board would be better. 8" to 12" out and 12" to 18" deep would also keep the groundhogs and whatnot from digging underneath your slab.

 

[DrewStyduhar]

Looks like mernards carries it. You guys ever used something like this?

https://www.menards.com/main/building-materials/landscaping-materials/landscape-edgers/8-black-plastic-lumber/1129976/p-4221069730084379.htm

 

[Midniteoyl]

Looks like mernards carries it. You guys ever used something like this?

https://www.menards.com/main/building-materials/landscaping-materials/landscape-edgers/8-black-plastic-lumber/1129976/p-4221069730084379.htm

View attachment 708503

Black or not, I'd get documentation of the UV resistance.

 

[DrewStyduhar]

Ill call them tomorrow. I mean, they sell them for use outside as landscape edgers. Mine would be buried. Ill get more info.

Drew

 

[nyone]

Why dont you backfill the exterior with dirt then the inside with gravel? I dont see the need for the extra board to begin with.

 

[mikester]

I'd put a 4 foot wide concrete skirt all around with a strong slope away from the barn. I don't want water or critters.

 

[deezler]

Even untreated wood would still last for years in the ground. With current basic ground-contact PT, I can't see how it would even rot within a decade. After which, yes the board loses structural integrity, but it doesn't just disappear and leave a void. Even if it did, after 10+ years, the gravel under the slab is going to be well compacted and fixed in place. It's not risky; just maybe not worth the $$.

It's really just up to you if you think the extra PT boards will assist your backfilling. To keep critters out from under your slab, concrete is definitely better long term. A 2-3' deep concrete rat wall is best.

But like midnightoyl said, you can just paint the PT boards first, and they'll be essentially waterproof.

 

[Xfaxman]

Looks like mernards carries it. You guys ever used something like this?

https://www.menards.com/main/building-materials/landscaping-materials/landscape-edgers/8-black-plastic-lumber/1129976/p-4221069730084379.htm

I used plastic deck boards on this old cattle guard, where the tin dirt blockers had rusted away. They worked well:

 

[Macinnis]

I just went through this with my building when I had the concrete put in.

what my concrete guys did was to put some gravel on the outside of the barn as to not let any concrete ooze out during the pour. They then leveled out all of the gravel inside of the barn up to the base of my concrete rat board.

so the 4” of concrete poured inside complete met/covered my concrete rat board.

once the concrete was done, the final grading was immediately done outside of the barn so that the gravel wouldn’t have anywhere to go during freeze thaw. I hope this is going to work.

 

[cqaigy2]

I've found that some of the "plastic" deck boards are actually a composite that includes wood product. In a wet climate, the wood in the deck board started to breakdown, leaving a spongy non useful board. That was some years ago, and maybe they are done something to fix that. I put PVC Azek on my small deck and i've used some of it in contact with the ground and it looks the same as new after 10 years. It's expensive though, that's why the deck is small.

 

[GLyford]

One way to keep metal from degrading where it is against PT boards is to use the peel and stick butyl flashing, like they use to seal around windows.

 

[DrewStyduhar]

Good info. I was thinking about laying the metal over the tar to do something similar. Maybe 15 felt paper

How would you guys handle the gap between the two skirt boards? Obviously nothing is perfectly straight so I could just push the new skirt up tight and shoot it in. I read where a guy intentionally left a gap and then came back with filler rod. He was concerned about water instruction between the skirts. Thoughts?

thanks again,

Drew

 

[GLyford]

I'd pack the gap with dirt and call it good...?

 

[DrewStyduhar]

Hi everyone,

Got sidetracked with some family stuff but finally got this done.

With lumber prices being so low again, I bought ground rated 2x10x16's for the second row of skirting. They were a pain to install alone since they were 16' foot lengths and wet! Maybe this tip will help someone but I ended up cutting some wooden wedges and set the 16' skirt on those. As I knocked on the wedges with a hammer it lifted up the bottom skirt and forced it tight against the top skirt. I was concerned about the new bottom skirt going crazy as it dried out so I cut 2x4s and bridged between the new and old skirt to try and keep things straight. After letting the bottom skirts dry out for two or so weeks, I tarred them with foundation waterproofer. I then bought 17 rolls of 29 gauge painted + galvalume tin and went to town. FYI, I measured slightly less than 13" from the bottom of the lower skirt to bottom of the rat guard. Coil stock comes in standard widths and one of those widths was 13-5/8" so it all worked out well. The tin is tucked up under the bottom of the rat guard ~3/4" and secured along the bottom every 2 feet with stainless screws. I have attached a few pics showing what I did.

My next project is to line the inside of the skirt boards with sheet foam. That extruded green stuff that Lowe's sell. Thoughts?

Here are some of my concerns:

- Putting a single sheet of foam across both skirts. The old and new skirts are slightly different in both size and alignment so its not like we are dealing with a perfectly flat surface here. I'm worried it may crack the sheets if I span both

- Bugs.....cant find much info but will bugs eat up the foam sheet?

- How thick should the sheets be? I am definitely getting concrete next year but still torn on radiant heat or not. Even if no radiant heat, I figure perimeter insulation and some underslab will help take the edge off when its cold. FYI, it only gets down in the teen temps here in NC. Frost line is like ~10 inches if I recall.

thanks in advance for any info/advice!!!

Drew

 

[Midniteoyl]

Looks good to me The 2x4's mid span is exactly what I did as well.

1.5" foam should work. Set it so it will be even with the concrete floor.

 

[DrewStyduhar]

1.5" foam eh? I thought Lowes and all them only sell 1" and 2".

I planned to remove the 2x4's mid span before installing the foam. Did you leave yours?

How do you attach the foam to the skirt?

What's the downside of just covering both skirts with foam and disregard where top of concrete will be. I know approx where the finished level of concrete will be but how that translates to its position on the skirting on other end of the building remains to be seen.

thanks!

Drew

 

[deezler]

Isn't your skirt board around the building perimeter perfectly level? Ideally it is, such that you don't need to use levels/lasers to float out the concrete; can just use the skirt boards as your guide.

For the foam, a technique I saw and copied on my pole barn build was to cut a 45 degree bevel at the top of the foam, for any boards on the inside. Then when you float out your concrete is can cover the foam and get right to the building edge without providing a thermal bridge to lose heat from.

 

[deezler]

By the way great job on the extra skirt board! Probably overkill on the tar waterproofing and paint, but hey, why not! Make sure to do some backfilling on the outside before you are compacting your extra new fill on the inside, so you don't bow the boards out.

 

[Midniteoyl]

1.5" foam eh? I thought Lowes and all them only sell 1" and 2".

I planned to remove the 2x4's mid span before installing the foam. Did you leave yours?

How do you attach the foam to the skirt?

What's the downside of just covering both skirts with foam and disregard where top of concrete will be. I know approx where the finished level of concrete will be but how that translates to its position on the skirting on other end of the building remains to be seen.

thanks!

Drew

Lowes' is Green: https://www.lowes.com/pd/Kingspan-I...d-Polystyrene-Foam-Board-Insulation/999972974

There's also Silverboard, pre-cut but cost more: https://www.lowes.com/pd/SilveRboar...ts-1-1-8-in-x-2-ft-x-4-ft-88-sq-Ft/1002916592

Doesn't need to be 1.5" though. 2" would also work just fine. 1.5", or greater, is for integrity and crush resistance. You can have it go up the wall as far you want. The recommendation to put it level with concrete was just for looks.

Here's a look at one with foam up to concrete and using in floor heating. You can see both the prep and the finished work in the vid (starts at right time).

Judging by your work already, you know what you are doing so just keep on going. It'll look and work good in the end, no worries