Moisture Vapor Barrier Calculator
Enter your floor area for the moisture-barrier volume, kits to order, and Part A/B mix — coverage, kit size and ratio editable.
Calculate Your MVB Volume and Kits to Order
Once a moisture test says your slab needs a barrier, enter the floor area and the tool returns the total volume, the kits to order, and the Part A / Part B split to mix. Coverage, kit size, and mix ratio are pre-set to industry-average values — edit any of them to match your specific MVB product's data sheet.
Product Rates
From your MVB product's data sheet.
Mix & Coats
The A:B split and how many coats.
Enter a floor area to calculate the moisture barrier.
Coverage assumes smooth, prepared concrete. Always verify coverage rates and rated moisture limits against your product's Technical Data Sheet (TDS) before ordering.
How the Moisture Vapor Barrier Calculator Works
- Confirm your slab needs a barrier — your RH or MVER reading exceeds your coating product's limit
- Check the coverage rate, kit size, and mix ratio — pre-filled with industry averages; edit them to match your MVB product's TDS
- Choose imperial or metric units and enter the floor area
- Choose the number of coats — one coat is standard, two coats for very high moisture readings
- Enable the waste allowance to add a buffer for edges and substrate absorption
- Review the volume, kit count, and mix quantities, then copy the results for your order
Examples
Frequently Asked Questions
What is a Moisture Vapor Barrier (MVB) primer?
A Moisture Vapor Barrier primer is a specialised low-viscosity epoxy applied directly to concrete before the main coating system when moisture levels are too high for a standard primer. It penetrates into the surface and cures to form a barrier that blocks moisture vapor transmission through the slab. Most MVB products are rated to 95–100% RH and 10–15 lbs MVER, compared to 75–80% RH for standard epoxy primers.
When do I need to apply MVB?
Apply MVB when your on-site moisture test results exceed the limits specified in your coating product's TDS. As a general guide: if your RH probe reading is above 85% or your calcium chloride test is above 5 lbs MVER, you should consider MVB. Above 95% RH or 8+ lbs MVER, MVB is typically required. Always check both the coating TDS and the MVB product TDS for the exact thresholds that apply to your products.
Does MVB replace a standard primer?
In most systems, MVB replaces the primer — it acts as both moisture barrier and bond coat. Some systems specify an MVB coat followed by a standard primer coat; others go MVB directly to topcoat. Always follow the manufacturer's application guide for the full system, not just individual products.
How many coats of MVB do I need?
One coat is standard for most applications. Two coats may be specified for very high moisture readings (above 90% RH or 10+ lbs MVER) or for below-grade slabs without a vapor barrier. Always check your product's TDS for its recommendation at the specific RH or MVER level you measured.
Does MVB fix a water leak or hydrostatic pressure?
No. MVB products manage moisture vapor transmission only — they are designed for slabs that are dry-looking but have high internal moisture vapor, not for active leaks, cracks with water ingress, or hydrostatic pressure from a high water table. If you have standing water, water coming through cracks, or hydrostatic pressure, those issues must be resolved structurally before any surface coating is applied.
Important Notes
- Always test moisture levels before deciding to use MVB — do not apply MVB as a precaution on dry slabs
- Confirm your MVB product's rated RH and MVER limits in the TDS before ordering
- Apply to clean, prepared concrete — MVB does not bond over contamination, oil, or surface laitance
- Allow the MVB coat to fully cure before applying the next coat — curing time varies by product and temperature
- Coverage assumes smooth, prepared concrete — porous or rough surfaces may require more product