Tar and gravel roof types are especially sensitive to roof penetrations. The whole roof must be able to shift around a little if it wants to. Its like a big floating membrane. A lag bolt thru the roof is a recipe for a leak. There is no solar collector system on the market that can attach securely to a tar and gravel roof...except the unique Powermat design.
Additionally, in climates where freezing is possible and systems must be winterised it can be difficult to remove all the water from a solar collector on a roof where the pitch is low or zero. The Powermat system is flexible so it can stay full of water and freeze solid each winter without fear of damage. However, the rigid header pipes and system plumbing must all be drained. Its much easier to simply drain the piping if you don't have to worry about the thousands of feet of small diameter tubes spanning header pipes. You can even elevate the header pipes at places so they will drain out more automatically. The system is very "flexible".
A typical drain scheme on a flat roof is to use a rubber connector (removable) as shown here so that you can quickly and easily fully remove the entire level of water from a header pipe or row of header pipes.
Its important to understand that if the absorber section (the part of the collector that is thin and spans the 2 headers) is exposed to freezing and isn't flexible it will burst right away. Most collectors on the market are not flexible and can not be installed at a low pitch for this reason. Also when pushing the limits of a pool season as is often possible you sometimes run into a night when the system hasn't been winterised and the temperature falls below freezing. That will burst a regular non-flexible solar panel and they aren't very repairable because there is no adhesive that works on polypropylene or similar mixtures. The Powermat absorber and headers are all pvc where exposed to the sun so they are fully repairable however you won't need that feature because they can withstand this kind of freezing, the kind that doesn't freeze 1.5" pipe solidly enough to burst it. This important feature allows you to extend the season and wait for that first frost before winterising rather than trying to guess when it will happen in advance missing many good solar days.
First you remove the bulk of the loose gravel from the area where the solar panels will be installed. You just need to be able to let the collector sit as close as possible to the tar and rock base below the loose gravel because that's what we want to stick the anchor plates to.
You simply assemble the collectors and couple them all together according to the installation manual
Then glue down the anchor plates with a big blob of tar or polyurethane or silicone or mastic.
I prefer to buy a bucket of "plastic cement" at Home Depot. This is a tar based adhesive that is used in the roofing trade to glue down the last corner of a row of ashphalt shingles.
Its real cheap but any goop like it works fine. What we want is a goop with enough body that it doesn't run off the anchor plate as we're trying to slip it under the collector as shown in this series of photos...
Cool eh? I developed this system in Canada where the first thing i did in business was wreck 3 tar and gravel roofs using the state of the art at the time. Strange that nobody else in this business has realised or admitted that you can't put bolts thru a tar and gravel roof and that not securing a solar heater is also a recipe for a broken mess in the backyard. I bought those 3 people new roofs by the way.
a Powermat solar pool heater for your needs
These pages are brought to you personally by Ken Wright, president of:
Hot Sun Industries Inc. ,
but first learn about the auto controls and plumbing, then fill in the form under "sizing"
