Hello dear forum members,
The severe hailstorm a few days ago badly damaged the twin-wall polycarbonate sheets on our old shed roof... ;-( Now there are several spots where rain is leaking in, and I was thinking of completely removing the twin-wall sheets, installing a boarding layer of rough-sawn boards or OSB panels, then nailing on a layer of 200g/m² (6 oz/sq yd) bituminous roofing membrane (or SICOTEC if the price is acceptable), and fully welding a PYE G 200 S4 membrane on top. Alternatively, using PYE G 200 S4 as the first layer and then covering it with PYE Photovoltaik 200 S5 or PYE Photovoltaik 250 S5 membranes.
Is this roof structure suitable for a shed roof? Are there better, more cost-effective solutions?
The roof is not intended to be used as a terrace or similar, but it should be safe to walk on two to three times a year for tree pruning, cleaning the porch roof, etc.
Boarding thickness of 21/22 mm (about 0.8-0.9 inches) might be a little thin, so I was considering 25/28 mm (1 to 1.1 inches). Is rough-sawn board better, or are OSB panels also suitable?
The shed is an attached timber-framed structure adjoining two adjacent precast concrete garages. It has approximately 12 x 12 cm (5 x 5 inch) posts and beams, and 10 x 18 cm (4 x 7 inch) solid wood rafters spaced 59–98 cm (23–39 inches) apart, with a maximum span of 3.90 m (12.8 ft) and a roof overhang of 60 to 80 cm (24 to 31 inches). The mono-pitched roof covers about 21 m² (226 sq ft), has an approximate slope of 3°, and is drained by a copper gutter.
My wife would really like to have the garage roof and preferably the shed roof extensively greened. I’m not quite comfortable with that yet. Not because of the appearance, ecological benefits, or waterproofing, or even structural reasons—since the FlorDepot system, saturated with water, weighs about 55 kg/m² (11 lbs/sq ft), which is only about half the load of the previous gravel covering—but because of the drainage of the porch roof over the garage and shed. My concern is that during heavy rain, the green roof with the vegetation mats might simply be washed away.
The porch roof is quite large: 11 m (36 ft) long and 2.80–5.30 m (9.2–17.4 ft) wide, with a 7° slope, and drains over the long side onto the garage and shed. Are my concerns unfounded, or am I maybe overlooking something else entirely?
Many thanks for your tips and suggestions!
The severe hailstorm a few days ago badly damaged the twin-wall polycarbonate sheets on our old shed roof... ;-( Now there are several spots where rain is leaking in, and I was thinking of completely removing the twin-wall sheets, installing a boarding layer of rough-sawn boards or OSB panels, then nailing on a layer of 200g/m² (6 oz/sq yd) bituminous roofing membrane (or SICOTEC if the price is acceptable), and fully welding a PYE G 200 S4 membrane on top. Alternatively, using PYE G 200 S4 as the first layer and then covering it with PYE Photovoltaik 200 S5 or PYE Photovoltaik 250 S5 membranes.
Is this roof structure suitable for a shed roof? Are there better, more cost-effective solutions?
The roof is not intended to be used as a terrace or similar, but it should be safe to walk on two to three times a year for tree pruning, cleaning the porch roof, etc.
Boarding thickness of 21/22 mm (about 0.8-0.9 inches) might be a little thin, so I was considering 25/28 mm (1 to 1.1 inches). Is rough-sawn board better, or are OSB panels also suitable?
The shed is an attached timber-framed structure adjoining two adjacent precast concrete garages. It has approximately 12 x 12 cm (5 x 5 inch) posts and beams, and 10 x 18 cm (4 x 7 inch) solid wood rafters spaced 59–98 cm (23–39 inches) apart, with a maximum span of 3.90 m (12.8 ft) and a roof overhang of 60 to 80 cm (24 to 31 inches). The mono-pitched roof covers about 21 m² (226 sq ft), has an approximate slope of 3°, and is drained by a copper gutter.
My wife would really like to have the garage roof and preferably the shed roof extensively greened. I’m not quite comfortable with that yet. Not because of the appearance, ecological benefits, or waterproofing, or even structural reasons—since the FlorDepot system, saturated with water, weighs about 55 kg/m² (11 lbs/sq ft), which is only about half the load of the previous gravel covering—but because of the drainage of the porch roof over the garage and shed. My concern is that during heavy rain, the green roof with the vegetation mats might simply be washed away.
The porch roof is quite large: 11 m (36 ft) long and 2.80–5.30 m (9.2–17.4 ft) wide, with a 7° slope, and drains over the long side onto the garage and shed. Are my concerns unfounded, or am I maybe overlooking something else entirely?
Many thanks for your tips and suggestions!
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