Blog & News / Are solar Roofs weatherproof?

April 11th, 2023
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4 min

Are solar Roofs weatherproof?

Roof is one of the most critical elements of the permanence of any house, providing protection from rain, wind and other weather conditions.

You can’t talk about a house without a roof. Most popular roofing materials are without a doubt roof tiles and steel. Today, however, solar roofs are becoming more and more popular. Two-in-one solar roofs can leave homeowners a bit skeptical at first glance, but they are just as much weatherproof as regular roofing materials. Let’s dive into solar roof waterproofness.

Solar roof water resistance

Solar panels, just like roof tiles or steel, can be a comprehensive roofing material. Solarstone has fired a 130 km/h hail ball at the panels, dropped the panels from a height of 1.5 m, passed fire tests and tested PV panels in a wind tunnel. Solarstone full roof panel can withstand a load of up to 5400 pascals (Pa) per square meter (m2), in other words up to ~550 kg/m2. We dissect Solarstone tiled roofs and full solar roofs separately.

Solarstone Tiled Solar Roof

Generally, a roof pitch of at least 18 degrees is required to install a tiled roof, which is a requirement set by the manufacturer. The same rule applies to Solarstone tiled roofs, and for roofs below 18°, a 100% waterproof sublayer (e.g. bitumen) must be used. On the side of tile interlocking solar module, there are two rubber seals on which a tile or another module rests, which prevent water from getting under the panels, creating a channel for draining rainwater. On the top, solar modules overlap, preventing rainwater from flowing back, for example in strong winds. It is important to note that with the right pitch, the top panel does not create shade to the bottom panel nor inhibit production capacity.

a side view of a solar panel leaning on a wall
an image of solarstone solar tiled roof with roof tiles

Solarstone Full Solar Roof

The 18 degree rule also applies here. In the case of a full solar roof, we are talking about large panels, i.e. standard sized solar panels to which is added the Solarstone Click-on aluminum profile, thus making basically any solar panel instantly into 2-in-1 roofing material. We in turn combine it with a passive panel (aluminum honeycomb composite) or other roofing material using transition flashings. The Click-on profile is added to the left, right and top of the panel. During installation, the left and right profiles gnash and create a water trap.

close up of solarstone solar full roof and click-on framing in rainy weather

Top profile is wider for panel overlap and has a PVC seal that prevents rainwater from running under the panel.

close up of a solar panel with solarstone click-on framing technology

Condensed water must be drained into the gutter using footplate and drip flashings (both hidden and exposed variation of gutter system).

a render of solar roof drip flashing installation process

Water leak hazards of other roofing materials

When it comes to on-roof solar panels (i.e. panels installed on an existing roof), waterproofing may not be the first thing that comes to mind. It is as if two layers of material are on the roof, and the only danger is the unprofessional handling of roof accessories. In the case of steel roofs, the main cause of roof decay is sheet metal corrosion, which occurs mainly at the standing seam where water accumulates to stand for a long time. Other main causes of leakage are penetrations, e.g. near chimneys and trapdoors. The disadvantage of a tiled roof is mostly loose and/or defective roof tiles, which allows rainwater to drip or flow under the roof. Insufficient roof pitch can also be an obstacle. As a rule, a slope of at least 18 degrees is required when using tiles.

No roof is 100% waterproof. Correct underlayment will allow condensation or minor leaks (caused by heavy rainfall) to enter directly into gutters or naturally ventilated areas. Choose your roofing materials carefully, a good roof will increase the value of the house!