Roof waterproofing · Metro Vancouver
Flat roof coating & restoration — commercial, industrial & residential
A seamless, fabric-reinforced liquid membrane laid over a sound existing flat roof or a new concrete roof deck. Every roof is inspected, and every existing roof is test-patched, before we quote the full job.
Restore or replace
If the roof is sound, it may not need to come off.
A flat roof that leaks is not always a roof that has to be torn off. Where the existing roofing is still dry, sound and firmly bonded to the deck, and the roof drains, it may be restorable in place, subject to an adhesion test patch: the wet and failed areas repaired, every seam, drain and flashing detailed, and the field sealed under a seamless, fabric-reinforced membrane. The sound roofing stays where it is and becomes the substrate.
Where the roof is not sound, we will say so. Roofing that has lost its bond across the field, a deck that is wet throughout, or a roof that holds water after rain is not fixed by a coating, and the honest answer is replacement or new drainage first. The inspection and the adhesion test patch decide which side of that line your roof is on, before you are asked to commit to anything. Our article on restoring or replacing a commercial flat roof sets out the questions that decide it.
We work across Metro Vancouver, from Vancouver, Burnaby, Richmond and Surrey to the North Shore, and out into the Fraser Valley. Commercial and industrial roofs come first: warehouses, plants, retail and office buildings. Residential flat roofs, strata buildings and new concrete roof decks follow the same process.
Who it is for
Roofs that keep the weather out, not roofs people walk on.
ResinTech RMS is a liquid-applied waterproofing membrane for flat and low-slope roofs on commercial, industrial and residential buildings. It goes on new concrete roof decks, and over existing flat roofing that passes an inspection and an adhesion test patch. It is not a traffic surface, so the parts of a roof that people walk or drive on regularly take one of our traffic systems instead.
| The roof | What goes on it |
|---|---|
| Commercial or industrial flat roof on a new concrete deck, with or without occupied space below | RMS, with the reinforcing fabric over the full surface |
| Residential concrete roof deck over living space, a garage or parking | RMS, with the reinforcing fabric over the full surface |
| Existing flat roofing on a commercial, industrial or residential building | RMS after an inspection and an adhesion test patch; fabric recommended over the full surface and always at seams, laps, flashings, drains and transitions |
| Roof terrace, or a walkway route to rooftop equipment with regular foot traffic | ResinTech PTS+ pedestrian traffic system, not RMS |
| Rooftop parking over occupied space | ResinTech VTS-D+ vehicular traffic system — see parkade waterproofing |
| New wood or plywood roof deck | Contact us to assess; new wood and plywood decks are not covered by the RMS data sheet |
The system
Two coats, one fabric, one top membrane.
The waterproofing is two coats of ResinTech FPU with a polyester reinforcing fabric between them. FPU is a flexible, crack-bridging polyurethane with 800% elongation and flexibility down to −35 °C. It stays tacky for days and is not made to face sun or traffic, so it is always covered with a UV-stable top membrane once it can be recoated, typically 8–12 hours after the last FPU coat, and within 72 hours. How each layer works is explained in our article on fabric-reinforced liquid roof membranes.
| Layer | Product | Wet film | What it does |
|---|---|---|---|
| Primer, only if needed | ResinTech CBE or TUE | Per the primer data sheet | Used only where the substrate or the test patch calls for it |
| Base coat | ResinTech FPU (FlexCoat-PU) | 25–28 mils | Flexible, crack-bridging polyurethane, applied after the details are done |
| Reinforcement | Polyester fabric, one layer | — | Full surface on concrete; recommended full surface on existing roofs, and always at seams, laps, flashings, drains and transitions |
| Second base coat | ResinTech FPU | 25–28 mils | Encapsulates the fabric; it can go on wet-on-wet as the fabric is laid |
| Top membrane | ResinTech PPM polyurea, or HPP polyaspartic | 18–20 mils (PPM) or 10–15 mils (HPP) | Covers and protects the FPU, which is not made to be left exposed |
| Colour finish, optional | ResinTech HPP or TCU over PPM | Per the product data sheet | Where a set colour or gloss is wanted |
In all, about 68–76 mils wet with PPM on top, or 60–71 mils with HPP, before any colour finish. Every coat is checked with a wet-film gauge. Values are typical figures from the ResinTech RMS System Data Sheet (RT-RMS Rev. 1.0); ask us for a copy.
- FPU elongation
- 800%
- Low-temperature flexibility
- −35 °C
- Top membrane on
- After 8–12 h, within 72 h
- Fabric laps, minimum
- 3 in sides, 6 in ends
How a roof job runs
Inspect, test, detail, coat, top, hand over.
- Inspect the roof.
The substrate, the drainage, the moisture condition, and every joint, drain, upstand and penetration. A roof that holds water after rain needs its drainage corrected first: RMS needs positive drainage.
- Apply a test patch.
On an existing roof, a small area is cleaned, repaired and dried as it would be for the full job, a patch of the system goes down and cures, and its adhesion is checked before the full job is quoted. The existing roof type is confirmed with ResinTech at the same time.
- Prepare and detail.
Existing roofs are cleaned, loose granules and failed coatings removed, and splits, blisters, open laps and wet areas repaired and dried. Concrete decks get a minimum 28-day cure, lose their laitance, oils, curing compounds and loose coatings, have high spots ground, and have holes and cracks repaired. Then drains, upstands, wall junctions, penetrations, corners and seams are reinforced with FPU and fabric before the field coats. Expansion and movement joints get their own joint detail.
- Lay the FPU and the fabric.
The first coat at 25–28 mils wet, the fabric rolled into it while it is fresh with laps of at least 3 in at the sides and 6 in at the ends, and the second coat either straight over it, wet-on-wet, or 8–12 hours later. The membrane is then inspected for pinholes, voids, exposed fabric and thin spots, and repaired before moving on.
- Put the top membrane on.
PPM, or HPP where the roof has to take light foot traffic sooner, applied once the FPU can be recoated, typically 8–12 hours after its last coat, and no later than 72 hours after it.
- Hand over.
The roof is kept closed and protected from rain until it cures. Batch numbers, film builds and weather are recorded, the finished roof is inspected for pinholes, thin spots and damage, and the record is yours.
The work runs in dry, stable weather only, with the roof surface at least 3 °C above the dew point and never damp, frozen or contaminated. FPU needs a surface between 5 and 35 °C; HPP needs a surface of 10–30 °C, air of 10–32 °C and humidity no higher than 85%. For a first look at your own roof, use our flat roof inspection checklist.
PPM or HPP on top
The standard top, or the fast one.
The top membrane protects the FPU underneath; the FPU and fabric do the waterproofing. PPM is the standard choice. HPP is chosen when the roof has to take light foot traffic within hours (3–4 hours at 23 °C), or when the owner wants a colour other than grey. Where a set colour or gloss is wanted over PPM, an HPP or TCU colour finish can go on top.
| PPM — standard | HPP — fast | |
|---|---|---|
| Chemistry | UV-stable polyurea, single component | Polyaspartic, two-component kit |
| Wet film over the FPU | One coat, 18–20 mils, never more than 20 | 10–15 mils |
| Colour | Medium grey | Tinted on site to any colour |
| Elongation | 648% | 20% — a hard topcoat, not a crack-bridging membrane |
| Tack-free | 2–3 hours (20 °C, 50% RH) | About 1 hour (23 °C, 50% RH) |
| Drying and cure | Through-dry in about 9 hours; full cure in 24–48 hours | Light foot traffic in 3–4 hours; protect from rain for at least 6–12 hours; full cure in 5–7 days |
| Choose it when | The roof needs the standard top membrane | Light foot traffic is needed within hours, or a colour other than grey |
What we won’t do
Where RMS is the wrong answer.
It is not a traffic surface. A roof terrace, or a walkway route to rooftop equipment that carries regular foot traffic, takes ResinTech PTS+, our pedestrian traffic system, and rooftop parking takes VTS-D+. If only part of a roof is walked on regularly, each area is specified separately.
It does not fix a roof that holds water. RMS needs positive drainage, and service under ponding or standing water is not covered, so the drainage comes first. Nor does the field membrane bridge expansion or active movement joints on its own: those get their own detail, which is the work on our expansion joints page.
RMS does not cover new wood or plywood roof decks; if yours is one, contact us to assess it. RMS is not for pools, tanks, potable water or submerged service. And we do not promise that it will bond to a particular existing roof before we have tested it: every existing roof gets an inspection and an adhesion test patch first.
Questions we get asked
Flat roof coating FAQs
Can you coat over our existing flat roof instead of replacing it?
It can be, if the existing roofing is sound, dry and firmly bonded to the deck, and the roof drains. Wet or deteriorated areas, splits, blisters and open laps are repaired first, and an adhesion test patch decides whether the membrane bonds to your roof. We inspect the roof and test it before we quote the full job, and if the roof is not a candidate we will tell you.
Which existing roof types can RMS go over?
We do not promise that in advance. Every existing roof is inspected and test-patched, and the roof type is confirmed with ResinTech before the full application is quoted. The test patch is what tells us whether the system bonds to your roof, not a list of roof types.
Can RMS go on a new concrete roof deck?
Yes. A new concrete roof deck takes RMS with the reinforcing fabric over the full surface, with or without occupied space below. The concrete needs a minimum 28-day cure and has to be sound, clean and dry; a primer is used only where the substrate calls for one.
Can we use the roof as a terrace or walk on it?
RMS is built for roofs that carry no regular traffic. A roof terrace, or a walkway route to rooftop equipment that gets regular foot traffic, takes the ResinTech PTS+ pedestrian traffic system instead, and rooftop parking takes VTS-D+. If only part of the roof is walked on regularly, tell us and each area is specified separately.
What is the difference between the PPM and HPP top membranes?
PPM is the standard top: a UV-stable polyurea in medium grey, one coat of 18 to 20 mils wet. HPP is the fast option: a polyaspartic that is tack-free in about an hour, takes light foot traffic in 3 to 4 hours and can be tinted to any colour, but it is a hard topcoat rather than a crack-bridging membrane. In both cases the FPU coats and the fabric underneath are the waterproofing membrane.
What happens if water ponds on the roof?
RMS needs positive drainage. Service under ponding or standing water is not covered by the system data sheet, so a roof that holds water after rain has its drainage corrected first, or it is not a candidate for a coating.
Can RMS go on a new wood or plywood roof deck?
New wood and plywood roof decks are not covered by the RMS data sheet. Contact us to assess the deck and we will tell you what it needs.
How is a roof priced?
After an inspection. The size of the roof, the condition of the existing roofing, the amount of detailing at drains, upstands and penetrations, and access to the roof are what set the price, so we do not quote a blind rate per square foot.
Roof assessment request
Tell us about the roof.
The more of this you fill in, the more useful our first reply. The existing roof type helps us plan the visit; the test patch is what decides whether RMS bonds to it. If water is coming in right now, call (604) 968-2040 instead — that is faster than any form.
Keep reading
Related pages
Expansion joints
Expansion and movement joints, which a roof or deck membrane must not bridge on its own.
Learn more →Structural concrete repair
Cracks, spalls and holes in a concrete deck repaired before it is coated.
Learn more →Roof assessments
Send us the roof. We'll tell you if it can be restored.
Photographs and a rough area are enough to start. We'll inspect it, test-patch it, and tell you what it actually needs.
Main (604) 968-2040
Second (604) 230-0256
estimating@westpacificcoatings.com