Replacing a flat garage roof is more than laying a new sheet. Here is what happens from the first look to the finished edges, and what to ask about before work starts on a Montpelier property.
A garage roof is one of the simpler flat roofs to replace, but it still has several stages that matter. The old covering comes off, the deck underneath is checked, new layers go on and the edges are finished so water leaves cleanly. In Montpelier, tight access and shared boundaries shape how the job is planned.
Looking before deciding anything
We start with the existing roof: how it is built, where it holds water, how the covering has failed and what the walls and edges look like. Inside the garage we look for daylight, stains or damp on the underside. That tells us whether this is a re-cover of a sound deck or a bigger rebuild, and whether a repair is still a sensible option.
Stripping back and checking the deck
The old covering is lifted off, and this is where the truth appears. Boards that have been damp for a long time can be soft or rotten and must be replaced rather than covered over. Where the deck is sound it is cleaned and prepared for the new layers. Anything found under the old covering is shown to you and explained before we carry on.
Falls, insulation and the new layers
Water has to run to the outlet, so we check the slope, correct low spots where we can and add insulation if the garage is heated or used as a workshop. Then the new covering goes on, using a single-ply rubber, fibreglass or felt system matched to the shape and use of the roof.
- Deck repaired or renewed where it needs it
- Falls checked so water runs to the gutter or outlet
- Insulation added where it suits the use
- New covering laid with sealed joints
Edges, upstands and the wall junction
Most flat roof failures start at the edges. New trims along the front, firm upstands where the roof meets a wall and sealed corners all help keep water out. A garage backing on to a neighbour's wall or a terrace boundary needs careful detail at that junction, and the gutter or outlet is checked so it carries water away freely. This may need planning or Building Regulations checks, and we advise before work starts.
Access, mess and finishing off
Tight Montpelier streets mean we plan where materials are delivered and where waste is loaded before we start. Old covering and rotten timber are cleared away, the area is left tidy and you are walked through the finished roof and given simple care advice. Weather decides the pace on a flat roof, because the deck must be dry before the covering goes down.
Frequently Asked Questions
Can the old covering stay under the new one?
Sometimes a new layer goes over a sound existing covering, but only if the deck is dry and flat. If the old layers are wet, blistered or rotten, they should come off so the problem is not sealed in.
Does a garage flat roof need insulation?
Not always. It depends on whether the garage is used as a workshop, a store or a room, and what is above or beside it. We explain the options so you can decide what makes sense for the way you use the space.
What should I ask before work starts?
Ask what will be done to the deck if it is found soft, how the edges and wall junction will be finished and where water will drain. A clear written description of the work means fewer surprises once the old roof is off.
Talk to our team about flat roofing in Montpelier
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.