BuildMeter guide · Excavation & Drainage
Foundation Drainage Board Planning Guide
Plan drainage-board area, laps, terminations and coordination with waterproofing and footing drains.
Direct answer
What to know first
Drainage board should be measured from the actual protected wall area, then increased for laps, corners and damage. It complements—but does not automatically replace—the specified waterproofing, footing drain and termination details.
Open Footing Drainage Board CalculatorPlanning workflow
- Measure the actual project geometry rather than relying on nominal dimensions.
- Separate open-field quantities from corners, openings, terminations and transitions.
- Use the selected manufacturer or approved detail to set spacing, laps, coverage or support rules.
- Apply a transparent allowance for cuts, damage and layout changes.
- Round to full purchasable packages or stock lengths and verify availability.
Worked example
Calculate drainage-board area from the actual foundation walls to be covered, then adjust for roll/panel dimensions and required overlaps. Termination strips, protection layers and outlet details are separate linear or piece-based quantities.
Decision table
| Decision | Verify | Why it matters |
|---|---|---|
| Measured dimensions | Site measurements and drawings | Nominal dimensions can misstate the actual takeoff. |
| Installation rule | Product data and approved detail | Spacing, laps and coverage vary by system. |
| Allowance | Complexity, cuts and damage risk | Detailed work needs more waste than open runs. |
| Package rounding | Supplier stock and usable coverage | Projects purchase full pieces, rolls or containers. |
Common failures
- Using nominal package coverage without deducting overlaps or cut losses.
- Applying one universal spacing or detail to every product.
- Ignoring corners, openings, end conditions and transitions.
- Rounding before all project areas are combined.
- Treating a material takeoff as a substitute for design or code review.
Professional boundary
Drainage board should be measured from the actual protected wall area, then increased for laps, corners and damage. It complements—but does not automatically replace—the specified waterproofing, footing drain and termination details.
Use the calculator for coverage planning. Final placement must coordinate waterproofing compatibility, footing drains, grade termination and manufacturer fastening/detail requirements.
Final field verification
Before using the foundation drainage board installation estimate as a purchase order, walk the project and compare the calculated scope with the installed conditions. Verify measured flow, run length, elevation change, pipe or duct size and available service access at the site. Photograph or sketch unusual details and keep the measurements with the estimate so another person can understand how the quantity was produced.
- Check equipment manuals and local plumbing or mechanical requirements before selecting spacing, insulation or operating assumptions.
- Plan cleanouts, valves, traps, discharge points and maintenance access before material quantities are finalized.
- Round only after all measured sections have been combined; rounding every small section independently can materially overstate the total.
- Recheck units, package coverage and the number of full stock lengths or containers required before checkout.