Removing battens from pitched roofs

Battens sit for years in damp, frost and summer heat. On a well-ventilated roof with treated timber they can last a long time. What counts is the actual condition of the wood, not the age of the roof. Whenever the roof covering is replaced, check every batten and test how firm it is.

These signs suggest the battens should be replaced:

• Dark, soft or crumbling wood, especially where it touches the tiles and the underlay
• Cracked, broken or loose battens that no longer hold the covering securely
• Leaks into the loft even though the tiles look undamaged
• Small holes and fine dust left by wood-boring insects
• A new roof covering with a different gauge (batten spacing) or different requirements for the base

Why not wait? Wet battens slowly damage the rafters underneath. The longer you put off the replacement, the bigger the repair to the roof structure may be later.

Good removal is more than ripping off old timber. It affects the condition of the rafters and how well the new roof build-up goes on.

1. Put up scaffolding or roof ladders, set up fall protection and fence off the area around the house so falling material cannot hurt anyone.
2. Plan the work for dry, calm days. Wet timber is slippery, and wind on the roof raises the risk of material, or a person, falling.
3. Strip the tiles or slates from the ridge down towards the eaves, which is the reverse of how they were laid. Lower them in a controlled way onto the scaffold or into a skip.
4. Remove the battens from the top down as well, using a pry bar and hammer. On newer roofs a screwdriver is often needed, because the battens are usually screwed down.
5. Loosen each batten gradually from both ends. Yanking out long nails by force often tears a chunk out of the rafter.
6. Protect the roofing underlay throughout. If the roof will stay open, cover it with a temporary tarpaulin.
7. Once the battens are off, inspect the rafters, purlins and wall plates. Only now can you see the real condition of the roof structure.

If the inspection reveals rot, cracks or insect damage, the load-bearing timbers are repaired before the new battens go on. Where the damage is extensive, it makes sense to call in a structural engineer.

How demanding the removal is, and so how long it takes and what it costs, varies from roof to roof. The main factors are:

• Roof shape: a simple gable roof has flat planes and battens of equal length, while a hipped roof has hips with angled battens and a larger area
• Pitch: on a steep roof the work is slower and fall protection is more involved
• Height of the house and access: scaffolding, a narrow street or a garden with no room for a skip all add time
• Details: dormers, roof windows, chimneys and valleys, where battens are cut short and the underlay is easily damaged
• A mansard roof, which has a different batten spacing on the lower and upper slopes
• Condition of the timber: rotten battens snap and take longer to handle
• Whether stripping the roof covering and waste removal are part of the job

Take care with older buildings. Many roofs still carry asbestos-cement sheets or slates. In most countries this material may only be removed by a specialist contractor who is licensed or registered for asbestos work. Nobody touches the battens until that covering is safely off.

Old battens are construction waste and should be sorted on site. Clean, untreated timber can usually go to the local recycling centre. Timber treated with chemical preservatives or coated with old wood treatments may count as hazardous waste. Check with your local council or the waste contractor how to dispose of it. Do not burn treated timber in a stove or in the garden, as the fumes are harmful to health.

Counter-battens are often in better condition than the battens. After checking and re-treating them, they can sometimes stay. Do not reuse battens that show signs of rot or insect attack: rot inside the wood is often invisible from the outside.

• Working without scaffolding or fall protection, or without fencing off the area around the house
• Leaving the roof open overnight or before rain without a temporary cover
• Tearing the underlay with a pry bar, which then stays hidden under the new battens and only shows up in heavy rain
• Ripping pieces out of the rafters by forcing the battens off
• Skipping the inspection of the roof structure, so the new covering hides damaged timbers
• No photos of the original condition, which would help with a complaint or an insurance claim

In practice, time is often saved on checking the underlay and rafters. Yet this is the only moment when everything is easy to reach.

Before the new battens go on, go through these points with the tradesperson:

• No nails or bits of batten left sticking out of the rafters
• Rafters not torn or split during removal
• Underlay intact, with any tears repaired using tape or a patch as the manufacturer recommends
• Damaged rafters, purlins and wall plates marked, with the repair method agreed
• Flashings around the chimney, dormers and roof windows checked and any damage noted
• Roof securely covered whenever work stops
• Waste sorted and removed, area around the house cleaned up
• Condition before and after removal photographed section by section