The free diy home improvement guide with answers to your questions on a wide range of do it yourself projects.


Flat Roof - Removing

An old flat roof may need to be completely removed and replaced if it has suffered form neglect and damp has penetrated to the point where the timbers have rotted. In the example pictures, the timbers are actually sound but the single storey extension under the roof is being replaced so the roof had to be removed first.

 underside of flat roof showing timbers in good condition

As with all demolition work, it’s best to work methodically. Not only does this make the job easier but, it’s far safer as well. You will need a skip for all the old materials being taken down and it’s best to fill this as you go along rather than having a large pile of rubbish to move again later.

Accessing the Roof

Before getting stuck in, you need to set up a suitable and safe means of accessing the roof. You can use a standard ladder, but if you have access to a small scaffold tower it can make life easier. Assess the stability and strength of the roof before walking on it. Old damp or rotten timbers and boards can give way easily so you will need to lay a suitable working board across the roof. Light Weight Staging or Youngmans type boards are suitable for this and can easily be hired. The purpose of these is that they can span a specified distance without any intermediate support. So, you can span one from one wall to the other to give yourself a working platform is the roof is not strong enough.

Removing Gutters

gutters to be removed from flat roof

Start by removing any gutters. With modern plastic guttering this will be a quick enough job as they can simply be unclipped. With older types this may be more involved. If the guttering is to be reused, store it logically so you know what’s what and keep it somewhere where it won’t get damaged. You can then remove the gutter boards and fascias.

Roof Covering

stone chippings on flat roof flat roof felt partly removed

The top side of the roof is covered with stone chippings. These can simply be swept up with a builders broom and shovelled into some rubble sacks. Don’t overfill these as they can be quite heavy and you’ll need to carry them down the ladder. With the stone chippings out of the way, you can start removing the felt covering. This is simply prised up at the edges and torn away. As with other demolition work, use work gloves and wear safety goggles to protect your eyes. Remove all the roofing felt methodically and dispose of in the skip.

flat roof boards part removed straw board used on flat roof

Roof Boards

A variety of materials are used to board the roof. In the pictures, Stramit was used. This is a composite board made from straw bound with cement. Working on one section at a time, use a wrecking bar to prise the boards from the timber joists beneath. Remove any nails left in the joists as you go along to prevent accidents. Once all the boards are off, the timber joists can be taken down. Construction methods vary, but a wrecking bar should be all that’s needed to release them from the top of the walls.

Roof Timbers

flat roof boards removed and joists showing flat roof furring pieces

With the timbers down off the roof, if they are sound and you intend using them again, prise off the furring pieces and de-nail. The furring pieces are wedge shaped along their length and give the upper surface of the roof a small fall to ensure correct drainage of rainwater from the roof.

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