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Building Science by Norman Aceron Garcia

Sump pump lids

by Norman Aceron Garcia

Sump pumpWater management strategies that help mitigate excessive water from accumulating in a home’s foundation often involve the installation of a sump in the basement or crawlspace. The sump is a small pit that extends through the floor slab and into the ground beneath to provide drainage containment for excess water. Accumulated water in the foundation can cause interior damage and promote the growth of mould, mildew, and fungus. Sump pumps should be regularly checked and maintained as per manufacturer’s recommendations to ensure reliable operation.

The sump pit should be provided with an airtight lid to prevent additional water management issues and poor indoor air quality. Sumps typically have standing water, so if the sump pit is uncovered or has an improperly sealed lid, water will evaporate into the home that can cause high relative humidity. Having a relative humidity of more than 50 per cent inside the house can encourage mould growth and elevated moisture levels in wood framings.

Open or loose-fitting sump pumps can also permit radon and other soil gases to infiltrate the interior spaces. Radon is a radioactive and carcinogenic gas that originates from the breakdown of uranium found in soil and rock. In high-radon areas, if soil gases are permitted to infiltrate the home, it can accumulate at potentially toxic levels.

The sump pump should be installed as per manufacturer’s specifications. Sump pump lids should be made of robust plastic or other rigid material (such as metal sheet) and be capable of providing airtight sealing with gaskets installed. The sump pump lid should have integrated sealing grommets for electrical wiring and a water discharge pipe. If the sump is installed in a concrete floor slab, there should be caulk around its pit. If the sump is installed in a crawlspace with a dirt floor covered by a vapour barrier, there should be approved vapour barrier tape installed around the rim.

A sump pump is installed to minimize accumulated water in a home. There are various models and types available on the market, but they all monitor the water level to prevent the water to go above a pre-set level and allow moisture intrusion or house damage. Although most sump pumps are useful in eliminating excessive water, they should be covered with an airtight lid to avoid moisture problems and radon infiltration into the home.

Norman Aceron Garcia, P.Eng. is an accredited professional in Leadership in Energy and Environmental Design specializing in Building Design + Construction. In 2015, Norman founded Mr. Peg Property Inspections, a social enterprise that advocates green building design and climate change adaptation strategies.

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