The most important part of your French house?

James Latter lifts the lids on roofs.

From a surveyorʼs point of view, a perfect roof is one which is completely weatherproof.
The architect will agree, with a ʻbutʼ – 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 (LʼAssociation 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 dʼantan (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 most important part of your house?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 plaques-ardoises fibrociment, the square ʻmanufacturedʼ 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 Ardèche
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
dʼAuge.
In the rural south and Midi, it is often the case that canal tiles are laid on the corrugated (fibrociment) 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 ʻersatzʼ 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.

This article appeared in French Property News, July 2003