Replacing a garage roof is more than laying a new sheet on top. The old covering comes off, the deck is checked, and the details at the edges decide whether it stays watertight.
A garage roof is a small area with the same weak points as a large one: the deck, the falls, the edges and the joint where it meets the house wall. In Cotham, many garages sit tight against tall Victorian walls, which makes the junction at the wall the detail that deserves the most attention.
Looking at the roof before anything is ordered
We start by checking why the roof is failing. Ponding, splits, lifted edges and stained ceilings inside the garage all tell us something. If the damage is local and the deck beneath is sound, a repair may be the honest answer. If the covering has failed across most of the roof, replacement makes more sense, and we explain which applies and why.
Stripping and checking the deck
Replacement means taking off the old covering back to the deck. This is the moment we find out what has been going on underneath. Damp boards, soft patches and rotten timber are cut out and renewed before anything new goes down, because a new membrane laid over a poor deck simply fails again from below. Anything doubtful is shown to you before we carry on.
Falls, insulation and the layers
Water must have somewhere to go, so we check the roof falls towards the outlet or gutter and correct them if needed. If the garage is used as a workshop or has a room above or beside it, insulation can be added at the same stage. The new covering is then laid in the chosen system, which could be single-ply rubber, fibreglass or a felt system.
- Deck boards checked, repaired or renewed as needed
- Falls corrected so water drains rather than sits
- Insulation added where the garage is used as living or working space
- Covering fitted in the system agreed with you
The edges and the wall junction
Most failures start at details rather than in the middle of the roof. We form proper upstands where the roof meets the house wall, fit edge trims so water drops cleanly into the gutter, and seal around any outlets, pipes or rooflights. On a Cotham terrace where the garage abuts a tall wall, lead or a purpose-made flashing is often needed to finish the junction neatly.
Finishing and what to ask
Before leaving, we clear the debris and check gutters and outlets are running. Ask any roofer for a written description of the work, what happens if the deck is worse than expected, and how the wall junction will be finished. Replacing a garage roof may need planning or Building Regulations checks — we advise before work starts.
Frequently Asked Questions
Can the new covering go over the old one?
Sometimes, but only if the old roof is dry, flat and sound underneath. Where there is damp or rot, it needs to be removed. We check the deck first and tell you honestly which approach suits your garage.
How long will the job take?
It depends on the size of the roof, the weather, the condition of the deck and the system chosen. A straightforward garage is a short job, but we only give a realistic timescale once we have seen what is under the covering.
What if the deck is rotten?
The affected boards are cut out and replaced before the new covering goes on. We show you what we find and agree the extra work with you first, rather than covering over a weak deck.
Talk to our team about flat roofing in Cotham
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.