Tips for renovating roof timbers in a French farmhouse

Nick Inman charts the ups and downs of renovating an old French farmhouse by himself.

21 August 2020
A farmhouse in winter in Normandy, France.A farmhouse in winter in Normandy, France.
By Nick Inman

Many a night, my wife and I have lain in bed having the same disagreement as we looked up at the ancient timbers supporting the roof of our loft bedroom. I say: “Aren’t they magnificent?” To which, she replies: “Magnificent at gathering dust and making the room so large it is impossible to heat.”

We are both right, but this is one of the times I got my way. I am never going to give up my romantic attachment to my oak and chestnut beams. They are one of the big reasons I bought this house. The charpente (wooden framework supporting the roof) of the typical French farmhouse is a work of art. Its purpose is to transmit the weight of the roof downwards to the earth without pushing the walls outwards and it does this through an ingenious design in which each piece of wood has a different function and name.

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Buying an old house

Charpente in a church belfry
Charpente in a church belfry

I have had to learn a whole new vocabulary, and I cannot help but admire the artisans who put this puzzle together without power tools, let alone computer-aided design software. Major structural repairs, and extensions, need to be done by an expert. Translation of trade names here can be tricky. The dictionary may give “carpenter” for charpentier but this a specialist roof repairer who deals with both timbers and tiles. However, the maintenance of existing roof timbers is a job for the home owner.

When you buy an old house, it is easy to be alarmed by the state of the roof timbers but appearances may be misleading. It is a fairly safe formula that longevity = solidity, as long as the roof covering is watertight. When we first moved in, I inspected the timbers and found them to be in a shocking state, deteriorating into flakes and dust. But that was all appearance. Outside, the softwood had been a meal for parasites but everything edible had long since been consumed. Inside, the beams’ heartwood was as sound as it was 200 years ago.

Many of the wooden dowels holding the structure together (iron nails were expensive back then and screws would have to wait for the Industrial Revolution) had rotted completely. They needed replacing with acacia substitutes – easily available from builders’ merchants and online.

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Clearing and choosing

Charpente in house under renovation
Charpente in house under renovation

All I needed for the timbers was to clear up anything loose, using chisels, wire brushes and occasionally an electric planer. For good measure, I sprayed everything with insecticide and gave all surfaces a generous covering of linseed oil. There are other ways to treat old timber, and plenty of products to choose from, and what you do is a matter of taste.

My dentist’s office is notable for its highly-eroded posts and lintels that have been stained dark and petrified. It is strangely calming to look at while I am waiting to be told to take better care of my teeth. Back home, I only had to replace one short piece of wood that was missing from one of the roof trusses for some inexplicable reason. Before the roof fell in, I bought a fat piece of oak from my local sawmill and laboriously cut it to size, creating a tenon to lock into the waiting mortice. The joint was then fixed fast with a new dowel and I expect it to last for another 200 years at least.

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