- Your roof-the most important part of your house?
YOUR ROOF-THE MOST IMPORTANT PART OF YOUR HOUSE?
James Latter lifts the lids on roofs.
- This article appeared in French Property News, July 2003.
- Probably the most important part of your house in France.
- From a surveyor's point of view, a perfect roof is one which is completely weatherproof. The architect will agree, with a ‘but' - it must look good too. In France you can have both. There are an amazing variety of roof coverings across the country, with regional variations and local style.
- Some of the most exquisite roofs are to be found in the Loire valley, where Angers slate is fashioned by the AOCDTF (L'Association Ouvrière des Compagnons du Devoir du Tour de France) to cover intricate small cupolas and turrets. This material is very expensive, so many new or restored houses will nowadays opt for the less expensive, heavier Spanish slate, but one which nevertheless gives an excellent finish.
- The tendency in the north of France is for tuiles plates on steeper pitched roofs, whereas in the south it is tuiles canales on shallow pitched roofs. Wherever you are, you will also have a choice between terre-cuite (traditionally hand made) or méchaniques' (manufactured and moulded) or béton, which are concrete. Lafarge make a range called terre de vigne, a terre-cuite, which is almost unrecognisable from the hand-made tuile d'antan (canale) - the real thing.
- Generally, you would expect the roof to equate to 7% or 8% of your house value, but if you get it wrong, maintenance costs and repairs mean it becomes a very expensive item. Your roof will only be as good as its supporting roof carpentry - the Charpente. A clean bill of health from your surveyor that the timbers are sound and not impaired by attack from wood boring insects or previous water ingress is essential. Over time, certain elements of a roof truss will have moved - oak will twist, pine will sag and (chestnut) pegs can rot or snap. The failure of any integral part can threaten the whole.
- The roof carpentry is therefore most important. This and the roof covering need to be well ventilated to maintain a good balance of humidity and temperature. The best way to ensure this is to provide a generous void between the underside of the tile and the upper side of the insulation of the habitable area. Ventilation tiles should be inserted to provide maximum air circulation, especially in slate roofs.
- The December 1999 hurricanes, which swept across northern France from the Manche to Alsace, and 18 hours later from Bordeaux to Limoges, wreaked havoc on roofs of all types, with traditional slate roofs being the most resistant. Whole corrugated iron roofs were found fifty meters away with timbers still stapled to the panels, which had acted as sails. Roofs of placques-ardoises fibro-ciment, the square 'manufactured' slates (which contain asbestos) suffered badly, but were quickly repaired.
- Couvreurs, who have had four good years as a result and were almost impossible to find, are now less busy and prices have eased. Most French artisan roofers are real artists. They take a delight in randomly mixing the various hues in terre-cuite tiles so the finished product has a soft feel, which inter-relates with the masonry.
- Local materials often play a part. You might find old agricultural buildings in the high Ardeche covered in Lauzes, which are large flat volcanic stones, whereas in Brittany a cottage with granite and schist walls might have a chaume (thatch) roof. The Norman thatch is often distinguished by irises planted in a clay bed along the ridge. Walls are frequently dressed with slate essandage and occasionally one finds chestnut shingles on the weather side of a colombage building in the Pays d'Auge.
- In the rural south and Midi, it is often the case that canal tiles are laid on the corrugated (fibro-ciment) roof of the original agricultural building or that this method was chosen to reduce the weight of tiles and the cost (you only need half the quantity). Whilst there is nothing intrinsically wrong with the 'ersatz' solution, two important points apply. Firstly, ventilation, as the roof void/underside becomes exceedingly hot, and secondly, the state of the charpente, which if attacked by beetle, quickly turns to frass and disintegrates. Ondulite, a similar product with a bitumen base is also popular as a support for canal tiles.
- Whatever choice you make, it is worth bearing in mind that a well laid roof will give character to your house, and could prove your best investment.