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How do i lay a garage slab 8mx6m

Hello. i just finished the ground work for my garage and im ready to lay the concrete slab, this is how i think i will lay the concrete slab
100mm of mot compacted down with whacker plate, then plastic membrane over the mot and then 100mm of concrete. questions
do i need sand ( if so 50mm Ok?) over the mot then lay the plastic membrane?

do i need any steel mesh (what size) in the concrete to stop it cracking?

can i lay a channel by the door to drain any water into nearby gully (prefered option) or should i raise the floor by 50mm to divert the water away from the garage entrance.

do i need to fit air bricks in the walls to keep the interior dry if so, near ground level or higher up near the roof which is best?

i would apprciate all answers and a big THANK YOU in advance.

2 Answers from MyBuilder tradespeople

Best Answer

I would recommend turning the plastic membrane up round the edges to finish above the finished floor level.Trim off later.This prevents any water from penetrating between the concrete base and the walls.I have often had to deal with this problem and believe me it is difficult to seal.


Answered 11th Mar 2012

yes sounds good to me ,sand blind ,dpm ,a4 mesh lapped @200mm incorporated in slab,you will need 8 sheets for this size of slab,lay aco channel connected to existing drain run,no real need for air bricks in a garage ,if you were going to use some as habitable space then yeah ,but no regs in a garage build ,ie cavity ,roof and wall insulations ect,so carry on my man ,at last a diyer with a bit o clout


Answered 7th Mar 2012

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