From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

Liquid-Applied Polyurethane Balcony Flashing Seam Calculator

Calculate the seam reinforcement/flashing material needed for a liquid-applied polyurethane balcony waterproofing system.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
82.02 ft
Schematic, drawn to the proportions you entered — not to scale on screen.
Who is doing the work?

Waste is set to 8% by hand. Pick a tier above to replace it, or keep your own figure.

Seam flashing needed

88.58 ft

High confidence

For the dimensions entered, expect a seam flashing needed of 27. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Total seam flashing = total seam/detail length × (1 + waste allowance), the standard method for estimating reinforcement fabric or flashing strips at seams, drains, and edge details in a liquid-applied waterproofing system

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

What counts as a 'seam or detail' in this calculation?
Any location in the liquid-applied polyurethane balcony system that needs reinforcement fabric or a flashing strip — perimeter edges, drain details, expansion joints, wall-to-floor transitions, and substrate seams should all be included in the total measured length.
Why add a waste allowance to the raw seam length?
Reinforcement fabric and flashing strips need overlap at splices and extra length where they turn corners or transition between details, so the material required is somewhat more than the raw measured seam length.
Does this calculator size the field membrane coating itself?
No — this only estimates the seam reinforcement/flashing material at details. The liquid-applied field coating volume for the balcony surface area should be calculated separately.