Vents and roof penetrations on a flat roof.
Anything that comes through the roof is a hole that has to stay watertight. Soil vent, mechanical ventilation, a cable entry for PV panels: each one needs a junction of its own.
Four simple steps
Request a quoteMeasuring and inspecting
I come out, measure your roof and look at exactly what it needs.
A keen quote
You get a clear quote with no obligation. No surprises afterwards.
We build your roof
Once you agree, we schedule the work for a time that suits you.
Handed over watertight
The roof is handed over fully watertight, with a 10-year guarantee.
Water running down a pipe on the roof?
Usually the collar around it is worn out rather than the roofing itself. Give me a call and I will look at it before it runs further in.
What this work includes
- Soil vents and air admittance
- Penetrations for mechanical ventilation
- Cable entries for PV panels
- Existing penetrations removed and sealed
- Hardened or cracked collars replaced
- Pressure equalisation vents and cowls
Vents and roof penetrations, and what you notice of it
Vents and roof penetrations
A penetration is torched or bonded into the roofing with a collar or a base plate, so the bitumen runs right up to the pipe and water cannot pass alongside it. If a new penetration is added, I make the opening, fit the cowl and finish the felt around it. If one has to go, the pipe comes out, the hole in the decking is closed and a new layer goes over the top that can no longer be seen.
The signs
During building work when the extractor or the mechanical ventilation is moved, when solar panels are fitted and the cables have to come inside, and on old penetrations whose collar has hardened and cracked. That last one is a common cause of leaks: the roofing is still sound, but the junction around it is not.
Why a penetration is so often the weak point
The roof area itself is one continuous whole: little happens there. At a penetration two materials meet that both move, one of plastic or metal and the other of bitumen, and they expand differently in the heat. After fifteen or twenty years the collar has hardened, a small crack appears and water runs down alongside the pipe. So with a leak I always start at the penetrations and the upstands, not in the middle of the roof.
What people ask about this
Yes. I make the opening, fit a penetration with a good collar and torch the roofing in around it, so the whole stays watertight.
No. Usually the collar around it is worn out rather than the covering itself. That is a local repair of half a metre or so all round.
Yes. The pipe comes out, the hole in the decking is closed and a new layer goes over the top, joined into the roof area.
What kind of roof is it?
The standard pipe that vents the drainage. Often the oldest penetration on the roof, and so the first whose collar hardens.
A thicker penetration with a cowl on top. During building work this regularly moves, and then the old hole has to be closed neatly.
The cables from PV panels have to come inside somewhere. A separate penetration with a good collar is safer here than running past the roof edge.
Comes up from the kitchen and often sits in an awkward place, close to an upstand or a roof edge.
On large areas, pressure equalisation vents are fitted so moisture beneath the felt can escape instead of forming blisters.
If an installation is taken out, a hole is left behind. The decking is closed and the covering runs straight over it.
Request a quote for vents and roof penetrations, no obligation.
Fill in the form or give me a call. I come out, measure it up and tell you what is needed. A 10-year guarantee on watertightness, and you are tied to nothing.
Roof leaks
Tracing the leak is part of the job. Urgent work is scheduled as soon as possible.
Roofs with solar panels
A roof made ready for panels, or repairs to roofs that already carry them.
Skylights and roof windows
Fitting and replacing, with an upstand that keeps the water out.