Using ash?

[ollysfollys]

I am getting the materials togwether for my conservatory and was wonder about what to use for the base, well infact if i can use ash like in the old days for flagging etc, i can get a load of it that i have used before with flagging and block paving but will it be ok for use above the hardcore/between the hardcore and DPM?

Is DPM strong, as ash is more course than sand and i dont want it to damage the DPM.

Other wise i will get sand.

Any help here please.

thanks wayne

 

[Blagard]

Just use sand.

While DPM's are fairly tough, anything sharp will go through it like a hot knife through butter. It is simply not worth taking the risk for the cost involved.

 

[ollysfollys]

Ok will do, thanks mate.

Just trying to cut back on cost but then sand aint expensive.

I am doing it this week so i hope the rain keeps off a bit.

 

[r896neo]

DPM is pretty tough and if your MOT is quite fine and well compacted you can get away without using sand as blinding. But for the price of a thin scattering of sand it's not worth the risk.

 

[ollysfollys]

Its fairly fine realy the ash.
I will need about 3/4 cubic m so at a guess it will be cheaper than sand as i can get 1 ton of ash for a tenner.

A bit technical this Q now but, how much does the MOT and hardcore compress /go down by. Not that it matters but more curious.

 

[RedHerring2]

From my own limited experience, I would suggest about 10% compaction. i.e. about 15mm for about 150mm of MOT.

Just a comment on using something other than sand.
I recently used quarry dust, classed as 0 - 3mm particles. About 13 Euros per tonne, I think, from memory. But the larger particles were a bit sharp. In the end there was no damage to the DPM, but it did worry me a bit.
You can't get soft sand here.

In future I would use quarry dust, then layer of insulation, then DPM, then layer of insulation, then concrete.
I couldn't get 100mm insulation here so I used 2 layers of 40mm anyway.

 

[noseall]

Ash!

Sulphate!!

Nooooooo!!!