DPC Cost Calculator

Formula Used

Sheets/liquid use area-based rates. Mortar DPC uses volume-based rates.

How to Use This Calculator

1. Enter the total wall length and pick the correct unit.
2. Set wall thickness and an allowance for edge cover.
3. Choose calculated width, or enter a custom DPC width.
4. Select DPC type, then enter the material rate.
5. Add primer and labor pricing, then apply waste and markups.
6. Press Calculate to show totals above the form.
7. Use the CSV/PDF buttons to export your calculation.

DPC Cost Planning Guide

Purpose and scope

Damp Proof Course (DPC) is installed within masonry to reduce rising damp from the ground. A sound estimate accounts for the DPC material, optional primer, labor, and realistic allowances for laps and cutting. Clear separation of these items makes the figure defensible in tenders and easier to revise when specifications change.

How quantity is measured

DPC work is often taken off as wall run length, then converted to installed area by multiplying by width. This calculator supports two standard methods: using wall thickness plus an allowance for edge cover, or a fixed sheet width taken from drawings. Use one method consistently across the BOQ to avoid mismatched comparisons.

Rate basis and material selection

Sheet membranes and liquid systems generally price per square meter because coverage is area-driven. Cement mortar DPC is more reliable per cubic meter because thickness controls consumption. The calculator switches the quantity basis automatically for mortar, so your rates align with supplier quotations and mix-based cost build-ups.

Waste, overlaps, and detailing

Waste allowance covers overlaps, roll ends, corners, junctions, and occasional handling damage during blockwork. Straight runs may suit 5–8% waste, while frequent corners, short segments, and penetrations can justify 8–12%. Enter waste as a percentage so unit rates remain clean and transparent during review.

Labor, sequencing, and primer

Labor can be priced per square meter or per linear meter, depending on how your crew or subcontractor is paid. Choose the basis that matches your quote. Primer is optional because requirements vary by product and substrate; when specified, it should be applied to clean, dry surfaces and allowed to cure as recommended.

Overhead, profit, tax, and quality checks

After direct costs (material, primer, labor), overhead typically covers supervision, tools, minor consumables, and site support. Profit is applied to the subtotal, then tax/VAT if applicable. Quality checks should confirm continuity at joints, correct lapping, and protection from punctures or debris before masonry proceeds.

Example data

Use these sample inputs to verify unit conversions and pricing layers, then replace them with project values. The example table below gives indicative ranges, but the calculator output depends on your selected rates.

• Sample A: 45 m length, 230 mm wall, 25 mm allowance, membrane rate 280 per m², labor 120 per m², waste 7%.
• Sample B: 120 m length, custom width 230 mm, liquid rate 350 per m², labor 45 per lm, waste 10%.
• Sample C: 80 m length, width 300 mm, mortar thickness 10 mm, mortar rate 18000 per m³, waste 5%.

FAQs

1) What DPC width should I enter?

Use wall thickness plus a small allowance for edge cover. If drawings specify a sheet width, enter that fixed width and keep it consistent across your takeoff items.

2) Why does mortar DPC use m³?

Mortar consumption depends on thickness. Using volume keeps quantities accurate when thickness changes, and it aligns with mix-based material costs and supplier pricing.

3) What waste percentage is reasonable?

For straight runs, 5–8% is common. Increase to 8–12% for frequent corners, short segments, penetrations, or tight logistics that increase cutting and lap losses.

4) Do I need primer?

Include primer when the product specification requires it or when adhesion is critical. It helps on dusty substrates, but only after proper cleaning and drying per manufacturer guidance.

5) Should labor be per m² or per lm?

Choose the basis that matches your subcontractor quote. Per m² suits area-driven installation and detailing; per lm suits pricing tied to wall run length.

6) How are overhead, profit, and tax applied?

Direct costs are summed first, then overhead is added, then profit, and finally tax/VAT is applied to the resulting amount. This keeps each pricing layer reviewable.

7) Can I export results?

Yes. After calculation, use the CSV or PDF buttons above the form. Exports include key inputs, quantities, and the cost breakdown for approvals and records.

Example Data Table

Sample scenarios for quick comparison. Replace rates with local market values.