Membrane roofing for Auckland flat roofs, decks and internal gutters

TPO is a single-ply sheet joined with hot air, so the seam is as strong as the sheet itself. There is no open flame during installation, which makes it the safer choice over an occupied building or close to timber framing, and the light surface reflects heat rather than holding it. It is what we specify on most Auckland homes.

Torch-on is a bitumen-based sheet bonded with a gas torch. It is heavier and more robust underfoot, which suits larger commercial areas and roofs that take regular foot traffic for plant maintenance.

We are certified applicators for both, which is deliberate. It means the recommendation you get is based on your roof rather than on what we happen to carry.

Under about three degrees of pitch, water does not run off fast enough for a profiled metal roof. It ponds in the pans, finds the laps and fixings, and eventually gets through. That is why a long run quote on a flat or low-pitch roof is usually the wrong product rather than a bargain.

Membrane is a continuous surface with no laps to fail, which is what a flat roof actually needs. It also handles the awkward geometry that flat roofs tend to come with: parapets, internal gutters, changes of level, and penetrations for flues and vents.

Decks, balconies, parapets and internal gutters are usually the same scope as the roof for us, and doing them together is cheaper than piecemeal. It also avoids a join between old and new work, which is exactly where roofs leak.

For a deck you will actually use, we install a walk-on grade membrane and can lay artificial turf, tile or timber over the top. Internal gutters get outlets sized to the catchment plus an overflow, so a blocked outlet cannot turn the gutter into a reservoir.

In a conventional flat roof the insulation sits between the joists, below the deck, which leaves the deck itself cold. Warm air from inside the house meets that cold timber and condenses on it, and people often mistake the result for a leak.

A warm roof puts rigid insulation above the deck with a vapour control layer beneath it and the membrane welded over the top. The structure stays warm and dry, and tapered insulation can build falls into a roof that never had any. The constraint is height, since the build-up adds 80mm to 150mm, so we check upstands at doors, windows and parapets before recommending it.