Moisture Control for Pest Prevention in Milwaukee

What did the 2010 cloudburst teach about water in Milwaukee?

The cloudburst on 22 July 2010 brought up to 7.5 inches of rain in two hours, according to the National Weather Service office in Milwaukee/Sullivan, and the city received at least 2,000 sewer backup calls. The lesson is that water finds the lowest point of a building quickly.

Water from a storm of that size runs to the lowest point it can reach. In a city, that can be a basement, a low corner of the yard or the sewer line, and the 2010 calls show that the water came back up the drains into homes that were not flooded from the street. A homeowner who has never had water in the basement should still treat the storm as a warning.

The lesson for moisture control is to plan for the water that comes in the worst storm, not the average one. The grade, the gutters, the downspouts and the drains are the parts of the house that move water away, and each should be checked before a storm rather than after one.

• Up to 7.5 inches of rain in two hours (NWS Milwaukee/Sullivan)
• At least 2,000 sewer backup calls in the city
• Plan for the worst storm, not the average one

How do you read the grade around the foundation?

The grade should slope away from the foundation, so that rain runs away from the wall. Soil that sits above the floor level or that is banked against the wall holds water against the foundation for longer than the rain lasts.

Walk the outside after a heavy rain and look at where the water stands. Water that pools against the wall, or that stays in a low ring around the house for more than a day, shows a grade that is not sloping away. Note the places on a sketch and take a photograph, so the change can be checked later.

Correcting the grade is a contractor's job and may need soil moved and compacted. The homeowner's part is to record the grade, to avoid piling soil or mulch against the wall, and to keep the wall base clear. A decision on regrading should be made on written quotes, and the work should be checked after the next storm.

• Walk the outside after rain and note standing water
• Photograph and sketch the grade
• Keep soil and mulch off the wall base
• Regrade through a contractor on written quotes

What do gutters and downspouts need?

Gutters need to be clear of debris and firmly fixed, and each downspout needs to carry its water well away from the foundation. A downspout that ends at the wall is a common source of water at the base of the house.

Clear the gutters in the spring and in the autumn, and check them after a storm with the most leaves. A gutter that sags holds water in its low point and spills it at the corner where it is least expected. The fixings should be checked, and any sagging run should be refixed or replaced.

Follow each downspout to where it ends. A downspout that discharges at the foundation should be extended with a pipe or a splash block that carries the water away. The extension is simple work, and a homeowner can do it or ask a contractor. A downspout that is blocked should be cleared before the next storm.

What should a basement or crawl space check look for?

A basement or crawl space check looks for damp patches on the lower wall, a white crust called efflorescence, a musty smell that follows the weather, and standing water on the floor. Each sign is recorded with its position and date.

A damp patch on a lower wall or in a corner is the first sign. Note whether it is recent or old, and whether it dries out. Efflorescence on a wall shows that water has moved through the masonry, and it is a record of past or present water rather than a diagnosis.

A crawl space should be checked from the access point with a torch, and only if access is safe. The homeowner notes the condition of the soil, any standing water and any sign of a sewer or drain problem. Where the crawl space cannot be entered safely, the check is left for a qualified person, and the homeowner does not make a guess.

• Damp patches on the lower wall and in corners
• Efflorescence as a record of water
• Musty smell that follows the weather
• Standing water and soil condition in the crawl space

What happens after a sewer backup or a flooded basement?

After a sewer backup or a flooded basement, the first step is safety: keep people and pets out of the water and call a licensed plumber or a restoration contractor. The pest work follows once the water is gone and the building is safe to walk.

Standing water after a backup can carry contamination and can be a shock hazard near electrical equipment. Keep children and pets out, and do not enter a flooded area until the power is known to be safe. A plumber or a restoration contractor handles the drain and the clean-up.

Once the water is gone and the building is dry enough to walk, a pest survey can follow. The survey records the water findings first, and the pest findings second. The homeowner should keep the contractor's records with the pest report, because both are part of the account of the building after the storm.

• Keep people and pets out of standing water
• Call a licensed plumber or restoration contractor
• Pest survey once the water is gone
• Keep the contractor's records with the pest report

How does moisture control fit a pest prevention plan?

Moisture control fits a pest prevention plan as the first layer. It changes the conditions at the foundation, and the sealing and inspection steps are then planned around the drier building.

A pest visit cannot dry a basement, and a treatment applied to a wet wall does not change the cause. The moisture work comes first, and the pest work is planned once the water is addressed. A homeowner who sees pests at a wet wall should check the grade and the drainage before booking a treatment.

This guide does not name a pest that moisture brings, because the sources this site relies on do not describe one for this condition. It describes the water as a condition to correct. The pest prevention plan is the combination of water control and the sealing and inspection steps on the other pages of this site.

• Water control is the first layer
• Pest work is planned after the water is addressed
• No pest is named for the moisture condition

What does a seasonal moisture calendar look like?

A moisture calendar sets the checks around the seasons: a spring check of the grade after the thaw, a summer check after heavy rain, an autumn check of the gutters before the leaves fall, and a check after any storm. The calendar keeps the water work ahead of the pest work.

In spring, the thaw shows where the grade has settled and where the downspouts discharge. A walk of the outside after the snow is gone is the first check of the year. The gutters are cleared and the downspouts are checked for their discharge point at the same time.

In summer, a heavy rain is the test. A homeowner who notices water at the wall base after a storm should record the place and the date. In autumn, the leaves are the main cause of blocked gutters, so the gutters are cleared before the heaviest leaf fall. A check after any storm finishes the cycle, and the record shows where the water went.

• Spring: check the grade after the thaw
• Summer: check the wall base after heavy rain
• Autumn: clear gutters before the leaves
• Any storm: check and record