Pads for decking

davek0974 · Post by **davek0974** » Sat May 18, 2024 2:55 pm

Has anyone laid something like 12x12 slabs on firm soil by using a spray PU foam?

It's for a tiny deck area and the slabs will be the footing for the stub legs to support it and spread what minimal load there will be.

The ground is firm compacted mud.

Thanks

dewaltdisney · Post by **dewaltdisney** » Sat May 18, 2024 3:03 pm

Just bed the slabs on pit sand, I laid some slabs using this method and they were fine for years.iwould be inclined to forgetthe deck and just have slabs, decks are always a nuisance at some point.

DWD

davek0974 · Post by **davek0974** » Sat May 18, 2024 3:30 pm

I would too normally but my friend wants it decked, another reason is cost - the area is very uneven and to level it will mean a skip, a lot of digging and then sand and slabs, its a 2.7m x 2.7m area, decking materials are costing at around £360 which I thought was pretty good.

Someone-Else · Post by **Someone-Else** » Sat May 18, 2024 3:35 pm

Don't use spray foam. It rots after a while.

davek0974 · Post by **davek0974** » Sat May 18, 2024 3:37 pm

Someone-Else wrote: ↑Sat May 18, 2024 3:35 pm Don't use spray foam. It rots after a while.

Even PU "weatherproof" variants?

dewaltdisney · Post by **dewaltdisney** » Sat May 18, 2024 4:17 pm

What about driving in some fence posts spike holders, the short ones would do https://www.toolstation.com/drive-in-post-anchor/p12179 they would take the wooden support legs.

DWD

davek0974 · Post by **davek0974** » Tue May 21, 2024 7:26 pm

Thanks all, I'll probably go with the spike holders.

One question, should the fascia/trim boards sit under the deck or level with the deck top?

dewaltdisney · Post by **dewaltdisney** » Tue May 21, 2024 7:50 pm

Best under to stop a moisture trap. If you wanted to be anal you could rout a drip sill under the edge and step the fascia back a notch.

DWD

davek0974 · Post by **davek0974** » Tue May 21, 2024 7:52 pm

Thanks

wine~o · Post by **wine~o** » Wed May 22, 2024 6:09 pm

davek0974, have you considered Padstones ? easily made up by digging out say 8/12 inches of soil then getting a level using wood to get everything to the right level followed by some postcrete or similar...

davek0974 · Post by **davek0974** » Thu May 23, 2024 7:42 am

Yes but on this task i was looking to avoid 99% of all digging wherever possible - the soil is compacted and totally root-bound by trees on the other side of the fence, it's like concrete.

I might swap back from the spike idea because of this and just scalp the loose surface, lay the 12x12's on either a sand, gravel or mortar bed and go with that, its not something I'm digging up for sure ;)