There are two fundamental options for fixing a pv system to a flat roof ballasted or mechanical.
Using ballast system on a flat roof.
Adds a lot of weight to the roof system typically 10 15 pounds per square feet.
But such a low slope holds snow and water much longer than a steeply pitched roof and therefore needs a very different material to stay watertight.
Fixing and installation options.
Screwing through a flat roof is not good practice as your friends have found out the hard way.
A ballasted system adds additional weight to anchor the array to the roof whereas mechanical methods cover two key practises either they penetrate the roof covering and are fixed to the deck or they do not and leave the waterproofing system intact.
Somebody walking on the roof will undoubtedly step on the ballast and put a hole in the membrane.
Ballasted flat roofs are a popular choice especially for commercial buildings.
There are pod systems available which are free standing and individually ballasted or you can use a mounting frame and ballast that with slabs.
Flat roof solar is usually free standing on the roof.
Drawbacks of a ballasted roof system.
It has a very low slope between 1 4 to 1 2 inch per foot so that it drains water.
Ballasted roof systems are simultaneously a roofer s best friend and arch nemesis.
A ballast system helps cut roof system application costs as it takes less time to install since sealing the layers together isn t necessary.
The easiest way to use flat roofs for photovoltaic systems.
Extremely difficult to find a leak in this system since the membrane is well hidden.
The panels can be mounted east west or south facing or in between depending on roof orientation.
Both factors can extend the life of your flat roof.
Simply put a ballasted roof is easy to install and basically guaranteed maintenance work for a roofer.
The s flex roof frame with ballast is the simple and proven solution for non penetrative green roof compatible flat roof installations.
It can also be a bit challenging to find a leak with a ballasted roof system and because the stones tend to collect a lot of dirt patching it can be a bit difficult.
The structure of the roof needs to be able to support the ballast.
Roofs with pavers as ballast can be used as outdoor patios.
The mounting frames are not secured to the roof and therefore the system has to be weighted down using ballast.
Holes mean roof leaks and roof leaks mean call the roofer.
The gravel can be applied in far less time than using a specially.
Specifically there are two main reasons to use a ballasted roof system.
A number of attachment and ballast options are available depending on the planned system and the conditions on site.
Ballast stone traps a lot of dirt making patching difficult.
The weight on a ballasted roof can be from 10 to 25 pounds per square foot meaning the substructure must be designed specifically to carry more weight than other roofing systems.
