Roof lifespan - what to check before making an offer on a house?
Replacing a roof is usually very expensive. Make sure you check these key points before making an offer on a property.
Will the property need a new roof or just a few repairs?
The age of the property, the roofing materials and whether the roof is pitched or flat will all affect the roof's durability.
Roofing materials naturally age over time without detriment to the roof's durability. However, high winds, frosts and snow and heavy rain all add stress to roofing materials. What to look for:
- Tell-tale signs that there may be issues with the roof include damp patches on the ceiling and stained plaster on the walls of upper floors. Sagging plaster is also an indication that water may have penetrated the roof.
- Tiles may crack or dislodge, mortar may become loose or lead flashing may tear, so check inside the loft space during the day for spots of light, which indicate missing mortar and tiles or damaged flashing. While you're in the loft space, examine the roofing felt and the trusses for signs of deterioration.
Take a pair of binoculars to the viewing to get a closer look at the roof externally.
- Consider the roofing material and how old it is.
- Ask the vendor if the roof has been repaired or replaced, either in part or whole; when the work was carried out and for any certification or guarantees.
- Manufacturers typically guarantee concrete or clay tiles for 30 years, although it is suggested that 60 years is a reasonable expectation of their service life. Natural slate roofs may last much longer – 120 years is not uncommon.
- Look for any gaps in the tiling, on both the roof's slope and along the ridge. Although replacing individual tiles should not be costly, you may have to consider more expensive repairs if there are several damaged areas.
- Lead flashing, used to seal between roof tiles and brickwork, will need repairing if it is torn. Are there signs of damage on chimney stacks, single storey extensions or in the valley where two sections of sloping roof meet?
- Check the fascia boards are intact. Usually fixed to the lower ends of the roof trusses they give support to the bottom row of roof tiles. Damaged or rotten fascias will need replacing.
- Look at the end of the roof at the gable where the verge tiles are finished off with cement. If there has been water ingress this may have cracked the cement bedding, causing it to flake and crumble away.
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Has the property got a flat roof?
Garages and outbuildings commonly have flat roofs, as do some single-storey extensions. They are typically covered in felt, although newer roofs may be of fibreglass or PVC.
- Damp patches on a ceiling may be a sign of a tear in the roofing material. Check outside for cracks and splits and uneven lumps.
- Is the roof completely flat? A sagging roof will hold water and the weight can cause the supporting boards to break.
How much will a replacement roof cost?
Replacing the entire pitched roof on an average 3-bedroom house may cost between £5,500 and £8,500. Expect to pay more for a slate roof as the materials are more expensive. A typical 6m x 3m flat roof is likely to cost about £1,200 to replace.
If you are concerned about the state of the roof, get advice and estimates from a couple of roofing contractors before making an offer on a property.