Flat roofs get replaced in spring because the covering needs dry weather to go down and bond properly. Extensions, dormers, garages and porches across this area are all on their second or third covering by now, and flat roof replacement produces a load that is consistently underestimated. The reason is that the roof is rarely one layer. Our Waterloo skip hire service covers a good deal of this work.
You are rarely stripping one roof
Here is the thing that decides the whole job. When a felt roof failed twenty years ago, the common answer was to torch a new layer straight over the old one rather than strip it back. When it failed again, somebody did the same thing.
So a roof that looks like a single covering from the ground is frequently three or four layers of built up bitumen felt, each one bonded to the last. Strip it properly and you are removing all of them, plus whatever was under the first one.
That is why the tonnage on these jobs surprises people so consistently. Bitumen felt is dense, and multiplied by four layers across a garage or an extension it becomes a serious weight from a modest area.
Mineral chippings are the hidden load
If the existing roof has a layer of loose stone chippings on it, and a great many older felt roofs around here do, that is the single heaviest element in the job and it is invisible from the ground.
Chippings were put down to protect the felt from ultraviolet and to give some fire resistance, and they were spread generously. A garage roof’s worth of loose stone shovelled off and bagged is a substantial weight before a single piece of felt has been lifted.
Bag them rather than tipping them loose into a container. They spread across the base of a skip, they are impossible to redistribute once they are in, and they will use most of your weight allowance if they go in first with everything else piled on top. Our page on skip size versus weight limits explains why that matters.
Clean stone chippings are worth keeping separate in any case, because they are inert material that gets recovered rather than disposed of. Our environmental and recycling page covers how the sorting works at our end.
What is underneath the covering
Once the felt is off, the deck is exposed and the news is often bad. Older flat roofs were decked in chipboard, which does not survive water, and if the covering has been leaking for any length of time the deck will be soft.
Wet chipboard is heavy, it comes up in unhelpful crumbling sections and it goes straight in the container. Plywood decks fare better and occasionally can be left, but on a roof that has failed it is generally a false economy.
Joists are worth checking properly while everything is open. This is the one chance anyone gets to look at them, and if the ends are rotten where they sit on the wall, that is a repair to do now rather than in five years with a new covering on top. Replacing a joist while the deck is off is a morning of work. Doing it later means stripping a covering that is only a few years old.
The fall is worth checking at the same time. A flat roof is never actually flat, and a good proportion of the ones that fail early do so because the fall was inadequate and water sat on the covering rather than running off it. If there are visible ponding marks on the old felt, that is what they are telling you, and firring the deck properly while it is open is far cheaper than doing it twice.
Any insulation coming out adds bulk without much weight, unless it has been saturated, in which case it adds both.
Do not burn the old felt
Worth saying plainly because it still happens on garage roofs. Bitumen felt burns readily and produces thick black smoke that is unpleasant, harmful and extremely visible. On a residential street it will be reported within minutes and it deserves to be.
It goes in the skip. Our guide to what you can put in a skip covers the materials involved.
Sizing and access
For a garage or a single storey extension roof, an 8 tonne builders skip is the usual starting point, and where there are chippings and multiple felt layers you should expect to be near the weight limit rather than the rim. Our builders skip hire for construction and renovation waste page covers how these loads generally run.
Position the container directly below wherever the material is coming off. Flat roof work is done from a ladder or a small scaffold and everything comes down by hand or by chute, so distance costs real time.
Waterloo sits within Sefton borough, so a skip on the road needs a permit from Sefton Council at £36 per month, covered in our guide to skip permits in Southport. On the terraced streets here that is frequently the only option, so get the application in early rather than the week of the job.
Local coverage
We run this stretch daily, covering Crosby skip hire and Seaforth skip hire alongside Waterloo, and our drivers know how tight these roads get once both sides are parked.
Ring us on 0151 909 6399 and tell us whether there are chippings on the existing roof. That one detail changes the size more than the area does. Our contact page is there if the roofer would rather deal with us directly.
