Post mix decking pads?

[con1_uk]

Hi, building a wooden frame for a raised composite deck, the deck will be fixed to the house on one edge (2.5m L x 2.5m W), clay soil, thinking of using post mix in a 100mm hole and plastic decking height adjustable legs. Will this be solid enough and how many will I need please?

 

[ree]

OP,
Consider that decks attached to the house often bridge the DPC course - and can cause splash up the wall?

 

[evdamadiynot]

I did mine on pads and also someone elses about a decade ago.Theirs even has a hot tub sat on it and is just fine.
Iirc there was a 300mm square x200mm deep pad every metre along the beams.
Treated those with old engine oil.

 

[con1_uk]

I am thinking of not putting wooden beams into the soil, just using the pads to place those plastic decking feet on to support the weight.

 

[evdamadiynot]

Id still put a deck- to-ground contact point every metre whatever method for future proofing
.

 

[con1_uk]

Yea, the deck will be supported with the plastic height adjustable legs which will be screwed to the underside of the timber subframe and will sit on the post mix pads I will make, does that sound ok please

 

[evdamadiynot]

As far as I can tell if theres enough of them

 

[con1_uk]

Excellent, thanks. Looking at 300 x 300 sized pads, what depth would you recommend in clay soil please?

 

[evdamadiynot]

depends on the load expected.
2OOmm perhaps, although youre getting into the territory of a solid concrete base

 

[trojanhawrs]

There is no advantage to using postcrete if you're not setting posts. Mixing standard concrete will be cheaper, stronger and give you more time to work.

 

[con1_uk]

Thanks for the replies so far guys, invaluable information cheers.

One last question, how do I make sure the slope away from the house is enough but not too much please? The ground around isn’t level so I can’t use that, sure I saw a utube video that said have the bubble on the spirit level touching the line, my deck is only 2.5m long but want to make sure no water stays on it. Cheers.

 

[trojanhawrs]

Make your pads level with each other, if you're using adjustable legs its not going to be difficult to create a slope is it? 1 in 100 is recommended (10mm per metre)