CALL TODAY! Ph: 1-800-565-LEAK (5325)
 Local Excellence Since 1978: Proudly Founded in Nova Scotia.

Waterproofing Your Basement Floor

It's more complicated than you think!

Water infiltration into your basement through the floor can be a serious problem causing significant damage to your home. Waterproofing your basement floor is the best way to prevent problems. Ideally, this would be done during construction, but often is not. If you need to waterproof your basement floor after the home is built, first, you must understand how and why water gets past your basement floor into your basement. Water can enter your basement by coming through:

  1. Cracks in the floor due to hydrostatic pressure 
  2. Floor/Wall joint due to hydrostatic pressure 
  3. Capillary action Vapour transmission due to differential 
  4. Condensation due to a cold floor and warm, humid air in the living space



Hydrostatic pressure is a technical term for water pressure. Simply put, the force of gravity exerted on a liquid at equilibrium; the weight of water bearing on an object. This happens when you have a high water table and insufficient drainage around the bottom of your foundation. The water table on the outside of the foundation will rise higher than the basement floor level causing the water trapped beneath the floor to come under pressure. As pressure builds, water will force its way into your basement through cracks in the floor and the floor/wall joint.

The PERMA-DRAIN™ System is designed to eliminate hydrostatic pressure.


Capillary action is when water is “drawn” upward, against the pull of gravity through narrow tubes in porous materials called “capillaries”. Your concrete basement floor is porous and if the water table rises to come into contact with the underside of the slab, water will migrate through the floor slab due to capillary action causing a wet floor.

PERMA-DRY®’s WATER-BLOCK™ is a formulation of cement, quartz, sand and proprietary chemiclas that penetrate into the pores capillary tracts of the concrete by osmosis, Brownian movement and dry particle reactions. The active ingredients in WATER-BLOCK™ react with various minerals in concrete creating crystalline growth which fills capillaries, pores, cracks and other voids in concrete. Due to the crystalline growth, larger water molecules will no longer be able to pass through the concrete while allowing smaller water vapour molecules to pass through eliminating vapour pressure. After it’s applied, WATER-BLOCK™ lies dormant until it comes in contact with water again at which time, crystalline growth starts again.

Ensuring water is not in direct contact with the foundation floor is also an effective way to eliminate water infiltration by capillary action. The PERMA-DRAIN™ System is the most effective way of draining water from beneath your foundation floor. by draining water from beneath your foundation before it builds to create hydrostatic pressure.

The PERMA-DRAIN™ System can be installed any time of year in any weather without costly, messy and environmentally un-friendly excavation from the outside!


Vapour Transmission occurs when moisture migrates from areas of high humidity to areas of lower humidity. The soil beneath and around your foundation is at 100% humidity and as we learned above, the concrete in your home is porous and when you combine that with basement humidity between 50-65%, moisture will naturally move from the soil through the concrete into the living space without a vapour barrier.

While the installation of a PERMA-DRAIN™ System will keep water from coming into contact with your basement floor and WATER-BLOCK™ will eliminate water infiltration via capillary action, the real problem that causes vapour transmission is the fact that the soil beneath your foundation is at 100% relative humidity all the time and is normally in direct contact with the concrete floor.

SEAL-CRETE™ is a clear, liquid penetrating sodium silicate based concrete sealer that can penetrate concrete and masonry surfaces up to 100mm (4”) deep. The sodium silicate seeks out and reacts with the natural salts (lime & calcium) in the concrete and reacts to for a silicate gel which hardens and densifies the concrete making it less permeable to moisture migration and vapour transmission. SEAL-CRETE™ is ideally used to prevent capillary action and vapour transmission, while remaining breathable.

In new construction, vapour transmission is achieved by the installation of polyethylene sheeting beneath the floor slab which prevents the moisture in the soil from coming into contact with the foundation floor. PERMA-DRY®’s DRY-COVE™ Air Gap membrane is a tough, three layer composite of recycled polyethylene sandwiched between two layers of virgin polyethylene extruded to form dimples which creates an air-gap between the concrete floor and the soil. DRY-COVE™ is much, much thicker and stronger than normal polyethylene sheeting (plastic) making it much more durable and resistant to damage from construction crews walking on it.


Generally, stale, moist air is heavier than dry air and becomes trapped in the lowest part of your home; the basement. On warm summer days with high humidity, the moisture in the air will condensate on cold, un- insulated basement floors or walls. Your walls and floors are so cold because concrete is a conductor of heat energy and at a soil depth of 2.45m (8ft), the soil is 10 ̊C (53 ̊F) even in the summer! This cold soil keeps un-insulated concrete floors and walls cold. When hot, humid summer air comes into contact with cold floors or walls, it condenses leaving water behind like water on the outside of a glass of ice water on a hot summer day.

There are numerous ways to correct condensation problems and prevent it in the first place. Over the past 25-30 years, new homes have had to have air exchangers installed which remove heavy, moist air from the basement and exhaust it to the outdoors. If your house doesn’t have an air exchanger, your local PERMA-DRY® location can supply and install a Humidex® to exhaust the heavy, moist air from your basement to the outside.

To further help reduce condensation, extruded polystyrene (Styrofoam) insulation can be installed beneath the concrete floor to act as a thermal break in order to help keep the floor temperature closer to room temperature. This is somewhat impractical to do in existing homes unless a major retrofit is being undertaken.

Waterproofing your basement floor is important to the livability and enjoyment of your home. If you are considering this, schedule a FREE In-home consultation for a customized waterproofing plan.