Image showing interior water damage
Water damage in basement caused by sewer backflow due to clogged sanitary drain

It’s no secret the cost of builder’s risk insurance has skyrocketed in many markets, accounting for up to 5% of project costs. Insurance experts cite several reasons for the escalating rates, with water damage as the top cause (over 30% of all construction-related losses).

Rising deductibles for water damage claims only deepens the pain. Insurers are bluntly telling home builders to absorb more and more risk. Yes, fire makes the headlines. But it’s water damage that continues to be the biggest threat.

What should you do to protect margins and reduce risk? Here are eight suggestions:

1. Scope the site. Where are the water threats? Is it rain? Groundwater? Surface runoff? Melting snow? In what direction? Also, check out the water table depth and groundwater flow. That helps guide excavation depth, foundation design and any dewatering requirement. Standing water is not only slip-and-fall hazard, it’s also a catch basin for contaminants.

2. Protect your material. Even if you plan just-in-time deliveries, stuff happens. Your team may take longer than scheduled. Maybe they finish faster. Or your supplier is delayed in receiving or shipping materials. Anything can happen and usually does in construction.

A safe, dry staging area is a safe bet. Ideally the materials are under cover, on pallets, wrapped in tarps or plastic.

3. Push water away. Erosion control may be mandated by local code. Silt fences help divert water away from the work area. A positive backfill at the foundation is an obvious technique to push water away.

4. Mark the grade. Once the finished height is determined, mark the waterproofing line as close to the grade as possible. Just make sure it’s not lower than six inches below the finish grade. Be especially careful with complex foundations and changing grades.

5. Channel water. Set perforated pipe – usually PVC or corrugated plastic – on a stone bed surrounding the home and backfill with rock to encourage water infiltration. This relieves hydraulic wall pressure and lets water harmlessly escape beyond the foundation wall.

6. Dry muddy areas. You may be working in a shaded lot that’s hard to dry. One proven method to dry wet soil is a lime application. Lime helps compact the soil and is particularly effective in drying wet clay and silt soils.

7. Talk to the neighbor. The neighboring property could be a surface water speedway. Take care to understand water flow. Work with the neighboring owner to mitigate spillover with barriers or diverters to temporarily safeguard your project.

8. Seal the foundation wall. Make sure the masonry foundation wall is fully cured before waterproofing the foundation surface. Asphalt-based bituminous membranes are often specified, applied with heat. The membranes are typically torched-on or applied as a self-adhesive.

Many contractors prefer a cold, fluid-applied, ready-mixed waterproofer. A latex-based product like DRYLOK Extreme Concrete & Masonry Waterproofer works great. The finish can be applied above or below grade and is guaranteed to stop water up to 15 psi, resists cat 4 (140+ mph) hurricane winds and reduces radon gas penetration.

No building site is 100% free from water hazards. Let these prevention strategies help reduce risk with a dryer, safer and more productive worksite.

Learn more about how to protect above- and below-grade project surfaces from moisture risk.