concrete base for garden summer house

[lilleville]

Hi. i'm installing a concrete base under a lilleville summer house. The ground slopes, so on 2 sides we'll need retaining walls and on 1 corner we'll need to build the ground up. The damp proof membrane will go between the type 1 and the concrete, but how do you stop the damp getting to the concrete when you backfill up to the level of the concrete so it is flush with the ground? Does it lie flat with the formers for the concrete edges on top, and then when you move the formers you fold up the dpm and backfill up to it and then cut it off level with the ground? How would you do it?

Thanks

LV

 

[Chukka63]

is there not a false floor to the summer house???,in which casde no DPM required under the concrete.you could raise the summer house on some treated timber bearers which would last for years and if they rot can be replaced with new ones.

 

[lilleville]

Ah-ha!! Thank you! Also do you know what grade of ready mix concrete I need?

 

[Chukka63]

Gen 1 or 6:3:1 if mixing by hand with seperate aggregates/cement or 5:1 using ballast and cement.doesnt have to be too hardy as its gonna be protected by the summer house as such.you can always add more cement if you like.

 

[Thermo]

whenever we put up a shed or any outbuilding on a concrete base we tack dpc to the underside of the bearers. As chukka says dpm will serve no purpose.

 

[Chukka63]

what about when rain/snow gets between the dpc and timber and sits there for ages and starts to rot the timbers ????.

 

[lilleville]

Thanks for all the response! Another thing, how would you hold the timber formers up? 2x2 stakes or re-bar? Which is cheapest?

 

[Chukka63]

just cut some pegs out of 2x1 tile batten.make sure you put enough in.2x2 is too hard to knock in.

 

[Thermo]

to hard to knock in, man or mouse chukka! Cut the ends at an angle to form a point, much more secure

we always do the base on a slight fall so it doesnt, in reply to your question about the dpc. always worked well. The dpc is cut to the same width of the batten