We have just moved to France. There is a lot of building work to do on the property that we have bought. Does anyone know if there are online sites or stores like screwfix to buy cheaper building materials.
Not sure how cheap you're looking to go, but for most forms of building materials, try Leroy Merlin, Bricorama, Bricomarché or for "serious" building materials, Point.P - all are bricks and mortar stores, but they have pretty reasonable websites.
Point.P is more "construction material" than simple "building material."
Building materials and tools are generally more expensive here!
There are companies (lamaisons for example) that can forward on items (from screwfix etc) for you.
If you're a large project, it might be worth buying most of it in the UK and hiring a van to bring it over....DON'T bring any electrical wiring / fuseboards (twin and earth etc) as it doesn't meeet the norms
Velux windows are cheaper in the UK, plasterboard is at least 1/2 the price in the UK, but is very heavy. Timber here is about the same price.