Marianne Suhr: Any old iron

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This month we have tackled a job that has been on the low priority list for far too long – our garage. Of course it wasn’t a garage when it was built. It was probably constructed around 1900 as a store to what was then a draper’s shop, now our front room. The structure was originally attached to the 400-year-old east wall, and we separated it last summer so that we could repair the ancient timber frame. But that’s as far as we got.

Surprisingly perhaps, the garage has probably always had a crinkly tin roof. Corrugated iron is a material that is much maligned but has been around since the mid 19th century and has saved countless historic buildings from decay by providing a cheap roof.

I suspect the present corrugated sheeting has been on the roof for the last 50 odd years. It is just starting to rust through and let water in above our timber store. When my partner Richard and I first talked about replacing it, everyone suggested we do it in ‘a nice plain clay tile’ instead. But I actually like this stuff. It’s entirely appropriate for an outbuilding, is easy to fit and lasts for ages.

The rather tricky bit was at the rear of the garage, where a beautiful climbing plant, a campsis, had grown over the back wall and roof slope, covering the southern face of the structure with stunningly lovely red bell-shaped flowers every August and September. This had to be carefully lifted back and pruned to get access for the work.

The old corrugated tin wasn’t going to give up without a fight. It took two chaps with lump hammers and angle grinders the best part of a morning to wrench it off. The flimsy timber frame then had to be repaired where the water had got in. It was a salutary lesson in just how much damage can be created in a short time by a leaky roof.

Once the new crinkly tin was on, my carpenter David began replacing the old shiplap boarding and overhauling the garage doors. We decided to use standard six inch feather edge board – and a chop saw and nail gun made relatively light work of the job.

Where we had separated the garage from the house, we had to create a new section of wall and back door to fill the hole. Here we took a measuredly extravagant approach and chose the more traditional (and more expensive) waney edged oak board.

Our glorious leak-free garage will now become a fully functioning workshop. The next task is to relocate the old kitchen units to store our collection of chisels, pointing tools, brushes, and, of course, the odd bucket of maturing lime putty. Richard is exultant at the prospect of sorting out all the odd nails and screws. Bring on the jam jars.

ABOVE (clockwise from left): Fitting the new corrugated steel sheet to the roof; detail of the new waney edged oak boarding and the ledged and braced back door; using a nail gun to fit the new feather edge boarding.

Corrugated sheeting: the inside track

• Commonly known as ‘crinkly tin’, the sheeting was originally made of iron passed through rollers to give it its corrugated profile. These days it is galvanised steel sheet.
• Holes can be temporarily patched with Evo-Stik Flashband (available from B&Q; diy.com), a self-adhesive flashing strip specially designed to cover small holes.
• When replacing with new metal sheet, be sure to get the traditional corrugated form, rather than the more widely available box section.
• When used with just the galvanised finish, the surface will start to rust in five to 10 years. For greater longevity, choose a protective powder coated finish.
• Get purpose-made fixings when buying the sheets. Follow the fixing instructions carefully and always fix through the ‘peak’ rather than the ‘trough’ of the sheet.
• To buy corrugated steel sheeting, contact Accord Steel Cladding (01384 364283; steelroofsheets.co.uk).

Know your boarding

1. External boarding comes in many sizes, profiles and timbers. The cheapest variety is six inch feather edge treated softwood, available as a stock item from most timber merchants.
2. For a better finish, boards can be cut to order in a variety of widths. Boards can have either a ‘sawn’ finish – with a rough surface – or planed. A planed finish is ideal if you’re applying a stain or creosote, or if you plan to paint it.
3. For a traditional finish, waney edged oak still has the bark left on, leaving a crinkly line. The bark usually falls off over time, so allow plenty of overlap.

WORDS & PHOTOGRAPHS MARIANNE SUHR
Featured in the April 2009 issue of Period Living