At some stage in a pitched roof’s life it is going to need more than just minor roof repairs. A well constructed pitched roof can last 50 years and longer but if a couple of lead valleys have gone, a few ridge tiles have cracked, some individual tiles or slates have slipped and there are leaks or condensation appearing in the loft then it may be time for a full refurbishment of your roof.
Creating a new roof on an existing house involves:
- Putting up scaffolding to eaves level
- Removing old tiles including ridge tiles and hip tiles along with mortar from ridges / verges. Dispose of or sell any tiles that can be reclaimed (unless you intend to reuse on new roof)
- Removing old wooden battens and disposing of in skip (if untreated timber then it can also be used as kindling wood for a wood burning stove)
- Remove any lead from valleys (there is scrap value in old lead)
- Removing old roof felt or torching and dispose of in skip
- Checking wooden rafters and joists are sound. Replace any that are rotten. Remove /hammer down all protruding nails
- Add new breathable membrane
- Add new pressure treated wooden battens at correct spacing
- Put on new tiles or slates or re-use old ones. Clay tiles will be hung on nibs. Slates will be nailed to battens
- Add roof ventilators if required for bathroom extractor fan
- Create new valleys (joins between roofs) with new code 4 lead or GRP
- Bed down any ridge tiles with mortar and bed down tiles on verges
- Add thermal insulation between rafters if cold roof (or lay insulation on floor of loft if cold roof)
- Remove scaffolding and leave site in tidy condition
- Remove skip
- Small terraced house: 1 week
- Semi-detached house: 2 weeks
- Detached house: 3 weeks
It is assumed here that the rafters and joists are reasonably sound. Where these all need to be replaced then there will be an additional cost for new roof trusses.
What does renewing a roof involve?
A new roof can mean all new roof tiles or slates or it may involve replacing those tiles which are damaged or have little life left in them. Clay tiles and slates can last for 100 years or more and concrete tiles 50 years plus. If the majority of the tiles are still usable then the ones that are damaged can be replaced with reclaimed tiles. Alternatively the older usable tiles / slates can be sold and an all new tile roof can be constructed.
How long does a new roof take to build?
Assuming an existing roof has to be removed and two people are working full time on the roof then typical timescales are:
Detached houses tend to have more complex roof designs with gables, hips and more valleys. That’s why it costs more per square metre than a terraced house which tends to have a very simple roof design. Scaffolding for detached houses tends to be more complex as well.