Pond liners... please, lift only once, if you can

Living roofs are a lot of labor. Especially dealing with several hundred pound EPDM pond liners, which are big and awkward to move around. So when you get the liner on your rooftop, make sure it’s going to stay there. We encountered some fun with the recent installation of our pond liner… let’s say we repeated the lifting of the 300 pound liner. Twice, actually. The circumstances were… a bit scary.

The First EPDM Lift

The pond liner for the upper roof of our straw bale & timber frame home is 30×35 feet, weighing in at over 300 pounds. Not something you want to spend a whole lot of time handling, really. The first day we carried it onto the roof, with the aid of a dozen people and scaffolding, and rolled it out into position on the roof. It was a relatively easy operation, a bit awkward given the nature of a giant sheet of rubber, but not the worst thing in the world.

However, we did not have rope ready in time to lash down the liner, and within 30 minutes the wind uplifted the entire sheet and deposited it (safely, thankfully) at the northwest corner of the building. Thankfully, no one happened to be standing there at the time.

Liner: Take Two

For the second lift, we had rope ready to lash down as soon as we positioned the liner, and we thought we were safe after that. And we were safe, for at least two days…. until a gigantic wind storm rolled in after midnight a few days later.

Let’s just say it was like waking up to a nightmare. During construction of Gobcobatron, and even after its completion, I’ve had plenty of bad dreams about the house, especially involving the roof — either the pond liner blowing away, the whole roof lifting off, etc. For some reason, a lot of my building nightmares involve the living roof.

Well, this time the nightmare was real, and I ran to the building site after waking up to the sound of intense wind, gusts blowing at least 40-50 MPH+, and witnessed the pond liner flapping, ready to take off. Rope was no match for the gusts here. It only merely slowed the uplift of the liner. Which it ultimately did in that horrifying 20 minutes of intense wind. (Thank goodness, rain did not accompany the wind.)

The whole liner hung from the edge of the roof, caught in the rope, and I quaked in fear that it was shred down the middle. We discovered the next day that the damage had been minor, thankfully — mostly consisting of a tear at the very edge on one side.

Almost ready to tie down...

The Final Take: Correct Installation of EPDM

The lesson was learned. It was obvious that the EPDM needed more than just rope tying it down. We overnighted a dozen ratcheting truck straps, and after the third raising of the pond liner, used those straps to tie and cinch down the whole thing in multiple places, especially along the edges.

If you are working with living roofs, and particularly, EPDM pond liners, make sure you have insurance against the liner flying away in the wind. Get yourself some straps and tie it down. Immediately. Especially for large roofs. Flying sheets of rubber can be very dangerous, and are very costly to replace if damaged.

Ratcheting straps -- use them.

Three lifts was enough for us, and hopefully one will be enough for you!