Paving on a garage roof

[rah]

I have recently had the roof above a double garage re-paved using slabs, but have drainage problems (water from the roof running down the walls of the garage). The house is in France and the roof is a beam and block roof with a reinforced concrete layer (which is waterproof) above the beam and block. The new slabs have been laid on lime mortar mixed with a waterproof agent on top of the reinforced concrete layer.

The slabs are designed to be laid without pointing or sand between them, and I suspect that the slabs have been laid on blobs of mortar rather than on a screed surface.

If I pour 30-40 litres of water onto the slabs, water soaks into the terrace (there is a fall, but the water "soaks" in rather than following the fall)....and then over several days after, the water oozes out of the lime mortar layer at the edge of the roof. The area of the terrace is 30 square metres.

I have stopped the builder doing any further work - and he hasn't any solutions.

Has anyone any suggestions, please?

[dig dug dan]

are you saying that the water is coming into the garage hrough the roof. If so, and I have done this before, it involved removing all slabs and what they are laid on (mortar blobs), then covering the roof with pond liner, and laying on to that.
However, you could paint the garage roof with liquid rubber, then lay the slabs on that. I used this stuff to seal a leaky concrete pond i built and it was superb, although a little pricey.
If not, it sound like you need a gutter or gully to take away the surface water, and run it to a downpipe.

[lutonlagerlout]

slabs should never be laid on lime mortar,unless it is hydraulic lime (which sets like cement) lime just isnt strong enough (got this from the chilterns conservation board) sounds like he has bodged it with a tommy special dib dib dab and a tap for luck
take them up,seal roof and relay on a full bed of 10:1 mix
cheers LLL

[Stuarty]

i dont ever lay slabs on any form of bed on a roof. We always lay them on little pads and shims. Its for easy access if the roof ever leaks. On the bigger roofs they are shaped with slight runs so the water is actually under the slab, running to a drain, either a gutter at the edge or drains in the roof itself.

see : http://www.caro.co.uk/index.php?section=Caro%20Systems

[seanandruby]

T roof needs ashphalting properly, otherwise, it will get worse.