Not every flat roof has open edges. This one in Chester is hemmed in by brick walls on more than one side, with rainwater and waste pipes running down the brickwork around it. That makes the wall junctions the most important part of the job.
We replaced the old roof with a new timber deck and an EPDM rubber covering, finished with upstands where the rubber meets the walls.
Laying the new deck
One photo catches the job part-way through, with sheets of new OSB going down over the roof and the old, chipping-covered surface still showing at the far side. Tools, a spirit level and cut offcuts are on the boards as the work goes on.
OSB is a good base for a rubber roof: large sheets, few joints and a smooth face for the adhesive. The level matters too, because a flat roof still needs a gentle fall to move water towards its outlet or edge.
Rubber at the walls
On a roof like this, water arrives from the walls as well as from the sky. Rain runs down the brickwork, and anything that gets behind the covering at the base of a wall ends up inside. So the rubber is not stopped at the wall line: it is turned up the brick to form an upstand, then finished off so water running down the face stays on the outside.
The finished photos show the new EPDM running wall to wall, with a neat black line along the foot of the brickwork where the upstand sits, and the sheet dressed down cleanly at the open side.
- New OSB deck over the whole roof
- EPDM rubber membrane bonded to the deck
- Upstands turned up the surrounding brick walls
- Edges dressed down at the open side of the roof
Talk to us about yours
Walled-in flat roofs are common on rear extensions and between the wings of older houses around Chester. If yours has damp patches near a wall or water sitting in a corner, the junctions are often the place to look. Our flat roof and rubber roofing page has more on how we work, and you can contact us for a visit.
To see a garage roof we rebuilt from the joists up, have a look at our replacement flat roof in Tarvin.
Questions About This Kind of Job
What is an upstand on a flat roof?
It is where the roof covering is turned up a wall rather than stopped at the base. It keeps rain running down the wall on the outside of the roof covering.
Why do flat roofs leak next to walls?
The join between a horizontal roof and a vertical wall moves slightly with the weather and collects run-off from the brickwork. If the covering is not properly turned up and finished there, water gets behind it.
Can you replace a flat roof with pipes coming down onto it?
Yes. Pipework is worked around, and the rubber is finished neatly at each wall and fitting so the roof stays watertight.
