The foundation rest on the footing which is usually poured directly on the ground surface. In most residential constructions no stone backfill should be found under the footing. The walls of the foundation rest on the footing.

The backfill under the basement slab is usually composed of a 3/4 inch net DB stones. The backfill serves as a drainage bed and protects against the ground-level humidity which tends to seep into the house.

If your building has a street-level garage, the garage slab is not placed on the same level as the basement slab. The backfill under the garage slab may be more than one metre in depth and should be composed of 3/4 inch DB stones.

In some types of buildings, the garage is on the same level as the basement. In this case, the same type and thickness of backfill will usually be found under both slabs. There should also be a deeper excavation near the garage door, to guard against heaving caused by freezing.

To Protecting concrete from sulphation the Building Code recommends contractors placing a polyethylene vapour barrier between the backfill and the slab. The vapour barrier will protect the concrete from sulphatic attacks.

Many excavation contractors and builders do not follow this recommendation. Trust Pyrite Pro for quality and professional excavation work in Montreal and on the South Shore. 514.594.2897

Damage to foundation walls In some cases, the lateral thrust of the backfill will produce cracks in the foundation walls. This usually occurs in basement walls, and garage walls were since the pyritic backfill level (ippg) is high. The swelling may cause the building’s foundations to heave and thus cause serious structural damage. On the South Shore of Montreal this type of swelling is often seen in older house with have a high level of pyrite.  Call now for a free estimate to get your basement pyrite removal or garage pyrite removal. 514-594-2897

The swelling of backfill can not be harmful  to your health .The Montérégie Public Health Department says the quantities of sulfuric acid are too minute to cause health problems.

To Protecting concrete from sulphation the Building Code recommends contractors placing a polyethylene vapour barrier between the backfill and the slab. The vapour barrier will protect the concrete from sulphatic attacks.

Many excavation contractors and builders do not follow this recommendation. Trust Pyrite Pro for quality and professional excavation work in Montreal and on the South Shore. 514.594.2897

Its important to be aware of the pyrite problem on the south shore of montreal. In scientific circles, awareness of the problems caused by the swelling of rocks containing pyrite dates quite far back. The first cases were reported around 1930 in the United States. In Canada, a very explicit text on pyritic clays in the Ottawa region was published in 1975 by the National Research Council in the Construction Digest. In the Montreal region, cases of swelling were reported as early as 1985.  Before buying an older house on the south shore of montreal call your excavation professional Pyrite Pro.