Concrete Crawl Space Retrofit. Polyethylene Over Existing Dirt Floor

The toughest details are those that have to match up with someone else's work, or those done — even done well — when energy was really cheap. These details are a collection of some common — and tough — dovetails of existing work with retrofits or additions. Bear in mind that green remodeling means creating a new operating regime that is better, not worse, than the one that may well have been working just fine before. Integration of energy efficiency, moisture management, and indoor air quality is much more important and challenging in remodeling than in new construction.

Foundations, Floors, and Walls Are Critical Green Connections

Air sealing is imperative. The connection between concrete foundations and wood framing is a place prone to air leaks and moisture problems. Wood is often warped, and concrete is rarely flat. There are at least three places for air to leak in and probably a lot more. Leaky connections can mean energy, moisture, comfort, and IAQIndoor air quality. Healthfulness of an interior environment; IAQ is affected by such factors as moisture and mold, emissions of volatile organic compounds from paints and finishes, formaldehyde emissions from cabinets, and ventilation effectiveness. problems. Extending the wall sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. past these connections is a good first step whenever practical. Caulks, adhesives, spray foam, and gaskets can seal them up tightly.

Keep water at bay

Unless you live in the desert, the ground is always wet; and that ground water is always pushing its way in. Footing drains can carry away bulk groundwater, but foundations also have to disrupt capillarity. Water in the soil will wick all the way up to the roof framing if you let it. CapillaryForces that lift water or pull it through porous materials, such as concrete. The tendency of a material to wick water due to the surface tension of the water molecules. breaks such as brush-on damp-proofing, sill sealer, and rigid insulation block this process. A foundation is a bad place to cut corners because problems are expensive and complicated to fix after a house is finished.

Manage the moisture in an old house

Existing foundation walls (and basement floors) are sometimes wet, usually damp, and seldom dry. Rarely do they have perimeter drainage systems, capillaryForces that lift water or pull it through porous materials, such as concrete. The tendency of a material to wick water due to the surface tension of the water molecules. breaks between masonry and wood (or soil) or insulation. To raise the performance of existing foundation and basement floors, you have to make them manage moisture BETTER than they currently do because you are going to insulate and air seal them, significantly decreasing their drying potential.

Learn more in the Green Building Encyclopedia:

Water management
Enclosure Overview
Foundation Drains
Foundations

DRAWING DETAIL

Download: PDF | DWG

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