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Dampproofing, Waterproofing and Window Wells

Temporary Services  | Surveying and Layout | Excavation | Footings/Foundation  |  Foundation Options | Subrough Plumbing & HVAC | >>Dampproofing, Waterproofing and Window Wells | Water and Sewer Laterals | Foundation Drain, Backfill and Rough Grade | Basement Slab

Once the forms are stripped from the foundation, the window wells and waterproofing can be started. It is usually a good idea to let the walls set a day or two to ensure that they are cured sufficiently.

Window Wells
The window wells are attached to the foundation wall with concrete anchors. The height of the window well is set 4-6 inches above final grade. The projection (the depth of the well from outside edge to foundation) of the well is determined by code. For bedroom wells the projection must be 3' which allows for easy egress. For all other rooms, the projection is 2'. The bottom of the window well should also extend a minimum of 6' inches below the bottom of the window. After backfilling gravel (4"-6") is placed in the bottom of the window well to facilitate draining. Care should be taken not to backfill too much dirt against the window well or they will bend and deform.

Dampproofing and waterproofing
It is quite common, especially in older homes or where water tables are high, for subterranean water to find it's way into basements. Dampproofing is the process of spraying a water resistant substance (usually black tar) on the foundation wall to repel water. It does not guarantee that water won't get in, so many contractors recommend waterproofing on new foundations.
Waterproofing is the process of placing a rubber membrane or spraying a rubber coating on the foundation walls. Even if the foundation develops hairline cracks, the rubber coating is flexible and will stretch with the crack. The contractor usually guarantees the coating for a certain length of time. Although it is more expensive, many contractors are waterproofing new foundations. It is well worth the extra expense especially where subterranean water exists.
Before scheduling dampproofing or waterproofing, the contractor uses paint to mark the height and areas to be sprayed for the installers. For existing basements there are now new leak stop systems that can be applied from the inside of the house. These systems just fix the areas that are known to leak.

Vapor barriers
Under crawlspace and slab foundations, vapor barriers are placed on the ground to prevent moisture from the earth from rising into the structure. A thin (6mil) plastic is placed on the ground often before the post and beams are installed. A barrier can be placed after the house is framed but it is a lot more time consuming at this stage.

Basement floors/slab on grade- Vapor barriers are placed under slabs to prevent moisture from rising into the slab floor. A thicker plastic is recommended because of possible punctures during the slab pour.

Notes to the owner builder
Dampproofing is a popular job for the owner builder to perform. Even though professionals use a spray gun to apply dampproofing tar, paint rollers work fine.
Installing window wells is usually a two man job but is not too difficult for the owner builder. A hammer drill and a concrete drill bit are the only specialty tools needed.
Vapor barriers can also be installed by the owner builder
. Where seams meet the vapor barrier should be overlapped about 12" and taped with a waterproof tape.

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