Roof batten replacement
In short
Battens are the timber the slates and tiles are actually nailed to, and when they soften the covering has nothing to hold. They fail from long-term damp — a leak left alone, condensation in an unventilated loft, or simply age in a roof laid before treated timber was standard.
Also called: Rotten battens · Batten replacement · Roof battens failed
Signs you need this
- Slates or tiles that will not hold a fixing anywhere in one area
- Battens that feel soft, spongy or crumble when pressed in the loft
- Visible dark staining or fungal growth on roof timbers
- A sagging or dipped line in the roof slope
- Damp insulation and a musty smell in the roof space
- Repeat slips clustered around the same section of roof
The batten is the least glamorous and most load-bearing component of a pitched roof. Every slate or tile transfers its weight and its wind resistance into a strip of timber perhaps 38mm by 25mm, and if that timber has softened then the fixing has nothing to grip regardless of how good the nail is.
They fail for three reasons. A leak that ran for a season or two soaked one area and rotted it locally. Condensation in a loft with no ventilation path kept the whole underside damp for years, which rots battens everywhere rather than in one spot. Or the roof simply predates the pressure-treated, graded batten that is standard now — untreated sawn timber in a Victorian roof has done well to last as long as it has.
Localised rot is a localised job. The covering comes off over the affected area, the soft timber comes out, new treated batten goes in at the correct gauge, and the slates or tiles go back. It is the kind of repair that is quick if it is caught and expensive if it is not, because rot spreads along the grain and into the rafter it is nailed to.
Widespread softness is a re-roof, and it is worth saying that plainly rather than quoting a series of patch repairs. If the battens are going everywhere then the covering has to come off everywhere to replace them, and at that point the job is a strip and re-lay whatever it gets called.
The gauge is not a detail. Batten spacing is set by the covering — the headlap the slate or tile needs at that pitch and that exposure — and getting it wrong produces a roof that looks fine and leaks in driven rain. It is one of the differences between a job done by a roofer and a job done by a general builder, and it does not show until the first bad westerly.
The other thing that comes to light when battens are exposed is the ventilation. Most batten rot that is not caused by an obvious leak is caused by moisture that had nowhere to go — a loft insulated at ceiling level with the eaves blocked by that insulation, and no ridge ventilation. Replacing the timber without fixing that is replacing it on a timer.
What the job covers
- Covering lifted over the affected area and the rot traced out
- Failed battens cut out back to sound timber
- New graded, pressure-treated batten at the correct gauge
- Rafter tops checked and treated where rot has reached them
- Underlay repaired or renewed where it has been disturbed
- Ventilation assessed, because damp battens usually mean a damp loft
What it costs
We don't publish a price for this yet, because a number pulled out of the air is worse than no number at all — your roofer has to honour it. On roofing it would also be close to meaningless: access is often the biggest single factor, and it varies enormously house to house. You'll get a firm price for your actual job when they ring you back, before any work starts. The quote itself is free and there's no obligation either way.
Common questions
How do I know if my battens have gone?
From the loft. Sound batten is firm and rings slightly when tapped; failed batten is soft, dark and gives under a thumbnail. The other tell is behaviour — if slates or tiles in one area keep coming loose no matter how well they are refixed, the timber behind them has usually stopped holding.
Can you replace battens without taking the roof off?
Only over the area you can reach, which means lifting the covering above it. For a localised patch that is a small job. For a roof where the battens have softened generally, there is no way round taking the covering off — which is why widespread batten rot effectively is a re-roof.
Why did they rot in the first place?
Long-term moisture. Either a leak that ran for a couple of seasons, or condensation in a loft with no ventilation path — which is the commoner cause and the one people miss. If it is condensation, the ventilation has to be sorted at the same time or the new timber has the same future as the old.
Does the batten spacing matter?
A great deal. The gauge is calculated from the covering, the pitch and the exposure to give the right headlap, and a roof battened to the wrong gauge will let driven rain past even though every slate is intact. It is invisible from the ground and it is one of the things worth asking a roofer about.
Need this doing in Macclesfield?
Tell us the job and it goes straight to our local roofer — one call back, usually the same day. Free quote, no obligation.