HOW TO SEAL A FLAT ROOF – A Flat roof need regular inspection and in order for them to keep the weather out and the inside dry, you must ensure that a flat roof is properly sealed. There is nothing worse than a leaking roof and it can cause untold damage to your house that will cost you dearly in the long run. In this guide we provide you with easy to follow steps and advice on the best way to seal a flat roof.
Inspect your roof and see if there is any loose or degraded felt. You can generally spot any deterioration to the felt as it begins to lift, bubble, crack and split. You may find that you have a problem in only one small area but DO NOT be tempted to leave it, as that one small area will allow water to penetrate and seep across the entire roof area, which can result in damage to the roof boards, joints, ceilings and walls.
Take a broom and thoroughly clean the area of roofing felt you are going to replace. Cut away any felt that is torn or degraded using a craft / Stanley knife. Once you have cut away all felt required, remove it from the roof and the area you are working in. The last thing you want is to trip over any debris laying around and falling off the roof.
Take a look at the timber sheeting or plywood under the felting. Make sure these are dry and treat or replace if necessary. If you do find that one or more of the timber sheets is badly damaged then, remove and replace them. If you do have to replace them check the joists when you remove them – you need to make sure that the timbers are dry and sound – this will only be necessary if the timber sheeting is rotten.
Take a can of bitumen and with an old brush apply a thick coating over the area. Make sure you overlap the surrounding felt by at least 8″ to create a nice water tight seal.
Cut a piece of felt that overlaps the existing felt to about 6″ and make sure you use plenty of bitumen. Press flat, with a length of timber, starting from the center and working your way out, on the new felt. This will ensure that the felt is bonded well to the bitumen underneath.
Take a hammer and some galvanized tacks. The tacks need to be long enough to penetrate the felt and be secured into the timber sheeting below. Tack the nails around the edges of the felt every 2″ or 3″. Once you have finished, check for any edges that might be sticking up and tack these down. Cover the edging with bitumen to ensure a water tight seal.