Butyl cellar lining - how best to glue to the DPM?

[Michael Kilpatrick]

Hello all,

we have a wine cellar (floor hatch) built into our new utility room as part of the extension - except that the builders got it wrong and tried to use something completely inappropriate to waterproof it: a paint-on bitumen emulsion which is only good for damp-proofing, not underground hydrostatic pressure. We need a proper membrane or impermeable solid construction.

The best solution would have been a rigid polypropylene box built-in before the utility room was constructed above it, but it's a bit late for that unless we dig out a little bit of the floor screed, etc.

Anyway, one solution is to make a box-welded butyl liner to drop in. But I really need to know exactly how best to weld this to the edge of the DPM to make the best all-round waterproofing. I want to eliminate the possibility of capillary action between the two mating membranes allowing water to creep up, over and into the cellar.

Anyone know much about the sorts of tapes and adhesives that could be used in this situation?

The construction is as follows:

The cellar has a base slab and an outer skin of blocks. It's 1.7m x 1.2m and only 0.7m deep. After the cellar DPC is installed there will be a screed slab and an inner skin of blocks, atop which will sit the framework for the hatches. Obviously you also need the inner skin to keep the DPC in place in the presence of any hydrostatic pressure.

The framework and inner blockwork have been demolished so we can start again with a waterproofing that actually works, but I think I need to be sure of the best way to adhere a liner to the exposed edges of the DPM around the hole so as to get the best all-round watertight seal. There are only three inches of the main damp proof membrane protruding around the edge of the cellar cavity. As the base slab, insulation and screed of the utility room have all been laid, exposing more of the DPM would require some breaking-in.

Michael (at mkilpatrick co uk)

[Steve Firth]

Umm, not necessarily. Polypropylene damp proof membranes are available as retro-fit options for both the wet side and the dry side of a structure. Obviously in your case digging out the entire structure isn't a great option - unless you are going to force the builder to do the work (as they should).

Have a look at Delta Lath which is a polypropylene membrane with a mesh welded to it to permit dry lining or a wet plastered finish.

've used this and the Delta-Drain membrane on the outside of a structure. It is extremely efficient and has solved the damp problems on a rubble wall which has an earth bank built against it.

Delta has an excellent reputation within the building industry. Particularly in civil engineering where Delta membranes are used to waterproof underground structures such as tunnels.

[Spamlet]

Your 'wine cellar' sounds rather like my 'inspection pit' in the garage. Always a bit damp. Not a problem, except where paper wine labels were used; but it kind of added an extra interest of 'pot luck' in choosing a bottle. Incidentally, it is surprising just how few bottles you can actually fit in a space that size. In the end I opted for a 6ft high 4ft wide wine cupboard instead. Can get stacks in there *and* read the labels without breaking my back. So, if it were my 'utility room' I would be making a nice cupboard and finding something else - fruit and veg/mushrooms/compost maybe - to go in the pit.

S