Cost of Repairing or Replacing a Roof Valley

All you need to know about having a roof valley repaired or replaced including costs of materials, costs of labour and time frames.

replace/repair roof valley

What the job entails

The roof valley is that part of the roof where two sloping roofs meet together, where rainwater has to be channelled downwards into a gutter. These roof valleys have to deal with a lot of water during heavy rainfall and are prone to leaking. Roof valleys are usually made from lead, concrete tiles or fibreglass. The method of repair will obviously depend on the materials used in the construction, but could involve a minor repair or complete replacement.

Once it has been established that the roof valley is damaged, then the first step is to remove the tiles/shingles along the valley which will allow you to remove the valley flashing. Take care to only lift up as many tiles as you need to get the new flashing into the roof. Then carefully fit the new flashing over the connection between the roofs and fix in place using mechanical fixings or concrete depending on the type of valley. If using cement or a waterproof adhesive then leave the flashing to dry completely before you start replacing/refitting the roof tiles, throwing away any damaged tiles and fitting new ones.

When any work is being carried out on a roof, a full inspection should be carried out on the roof tiles, flashing, chimneys, fascia/soffit and guttering. Labour is often the most expensive part of a quote for any roof related repairs, so it makes sense to get any roof repairs done at the same. In addition, tiles will quite possible be disturbed/broken during a repair to the roof valley, so spare tiles should be on hand prior to starting the job.

In the majority of cases, a complete replacement of the roof valley and cement is the best option. However, sometimes the roof valley itself is in good condition but the cement is in poor condition and crumbling, so it can in some circumstances be possible to just re-bed the tiles onto new cement, leaving the existing valley in place. But if the base for the roof valley is concrete tiles, then they will almost certainly need to be replaced as it is almost impossible to repair concrete tiles and they are prone to leaking.

A full replacement of the valley will involve removing all the tiles, all the cement and also the under-felt (which is usually rotten anyway). If you have a bad water leak coming from a faulty roof valley, where water is staining the ceiling of the floor below, you need to replace your roof valley before serious damage is caused to the building structure. Lead valleys can be repaired which is handy as they are a particularly difficult to dispose of being toxic.

With any job where roof tiles are removed, you will find that some are damaged, or you will actually break them in the process or removing/refitting - so always have spare tiles to hand. Though most tiles are not expensive so this is not a major problem in terms of cost. If the existing valley flashing is lead and this needs removed then do not simply through this away! Lead is toxic and needs to be disposed of correctly, but you may find your local scrap merchant will actually pay you for any lead flashing you have that is surplus to requirements!

Replace/Repair a Roof Valley Cost

To replace cement only and re-use existing valley flashing, then you are looking at around £300 to £375, for a full replacement add on around £100-150. This assumes typical replacement with cheap easy to access roof tiles and easy access to both the house and the roof valley itself.

Most roofers work in pairs and usually charge around £250 per day between them. In terms of times frames you're looking at around 4-6 hours to repair a roof valley or around 6-8 hours to fully replace.

Here are a few average costs for hiring someone to repair/replace a roof valley:

# of Valleys Repair/Replace Avg. Cost Duration
1 Repair £350 1/2 a day
1 Replace £450 1 day
2 Repair £450 1 day
2 Replace £750 2 days


Cost Breakdown

Individual costs for hiring a roofer to replace a single roof valley - Total Cost: £450

30%

Materials & Waste
£135

50%

Tradesmen
£225

20%

Scaffolding
£90

FAQ's

Assuming a typical size roof valley of up to 3 metres in length, standard roof tiles and no access problems, than it will usually take around half a day to replace the cement and simply re-bed the existing valley into place, but if you need the complete valley replaced then it will take a full day to complete the job.
The roof over your head is one of the most important structures of your home, protecting you and your belongings from the elements. When you are considering any roofing work being carried out, using an NFRC (National Federation of Roofing Contractors) member contractor to carry out the work is a good start and will give you some peace of mind.

The National Federation of Roofing Contractors is the largest roofing trade association in the UK and all members are rigorously vetted to ensure a satisfactory trading record, high quality skills and technical competence, satisfactory insurance cover, full compliance and knowledge of current health and safety legislation, and full compliance with the Government-endorsed TrustMark scheme to help the public find reputable tradesmen to carry out work on their home. But always gather at least three quotes and pay careful attention the recommendations given - do not simply go for the best price, when it comes to roofing the quality of work is just as important.
Working on roofs is not recommended unless you have the necessary qualifications, experience and equipment. Working on old roofs is not only dangerous to those doing the work, extensive damage to the roof itself is a real possibility which would make the DIY job far more expensive than hiring a competent roofing contractor in the first place! Roofing is hard work and the weather in the UK makes it not only dangerous but also pretty uncomfortable! You also need to fit enough to work at height often carrying heavy tools and materials. Roofing is definitely not for everyone, but if you are fit and comfortable working at heights, pus have ball the necessary tools and safety equipment required, it is possible to work on your own roof if you are determined!