Inverted Roof Insulation

Inverted roofs have their waterproofing layer beneath the insulation instead of above it as in other forms of roofing. It is the insulation for protected membrane flat and green roofs. Insulation boards are loose-laid on top of the waterproof (usually a liquid-applied) membrane and then weighted down with paving slabs or gravel ballast. 



The inverted roof insulation protects the membrane from extremes of weather, such as frost, UV exposure and the expansion and contraction that comes about from summer/winter temperature cycles. The standard design consideration is that the rain falling on the roof filters through the ballast and between the insulation boards until it reaches the membrane, and then drains away through rainwater outlets. Such insulation is expected to be wet for the majority of its lifetime, and also one has to remember that some water is almost always trapped beneath the insulation boards by capillary action.

During a heavy rainfall, the membrane can become chilled by the water that filters through the ballast and insulation and then sits on top of the membrane, creates a risk that condensation could occur within the build-up of the roof.  In the majority of cases, any condensation that occurs will evaporate once the membrane has warmed up, with no accumulation of condensate. So, the waterproofing must be done on a quite dry surface, and also make sure than the waterproofing membrane doesn't have any cracks. The roof surface must have a correct slope carry the rainwater to draining outlets.

Types of Products
  • Rigid Insulation Boards,
  • Membranes
Rigid Insulation boards
  • Kingspan Styrozone N300R and Styrozone H350R Flat Roof XPS Boards are highly effective rigid insulation boards made from extruded polystyrene core covered with smooth skin on both sides. It is especially designed for protected membrane flat roofs and for green roofs as a popular alternative to traditional roofing systems, whereas its high comprehensive strength makes it ideal for inverted roofing.
  • Cellecta Hexatherm XROOF 300L is an extruded polystyrene thermal insulation board designed specically for inverted roof applications where a high resistance to compression and water absorption is essential. XROOF roof insulation boards are ideal for a multitude of roofing requirements, including pitch roofs, inverted flat roofs, flat roofs and green roofs.
  • Cellecta Hexatherm XDRAiN is a high performance extruded polystyrene inverted thermal roof boards, featuring integrated drainage channels on their underside, which speeds up the shedding of rainwater from the roof, eliminating the need for a separating drainage mat, making them ideal for green roofs. Manufactured in accordance with BS EN 13374 and tested to BS EN 12267.
  • Cellecta Hexatherm XMD is a high performance extruded polystyrene thermal insulation board bonded to a 6mm thermal laminate facing, suitable for vertical upstands. It combines the benefits of high performance extruded polystyrene with a facing board to produce a composite thermal board to suit a specific application. Manufactured in accordance with BS EN 13374 and tested to BS EN 12267.
  • Sundolitt XPS300 is an extremely durable thermal insulation board made of extruded polystyrene offering exceptional thermal performance and versatility. It is a lightweight board that is able to withstand extreme loads. Sundolitt XPS300 is highly water resistance, so can be stored and installed in severe wet weather conditions with no deterioration during its life. It is easy to cut and customise on site and requires no special equipment or tools.
Membranes
  • Kingspan Aquazone is a high performance non-woven polyethylene membrane suitable for use on inverted roofs finished with gravel ballast, green roof systems and concrete pavers on appropriate supports. Kingspan Aquazone can can dramatically minimise the cooling effect associated with rainwater flowing down through the insulation and draining away. It can significantly reduce the insulation thicknesses required to achieve specified Uvalues.



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30mm Kingspan Styrozone H350R Flat Roof XPS Board (pack of 14)

30mm Kingspan Styrozone H350R Flat Roof XPS Board (pack of 14)

1250x600mm - 10.50m2  show quantity discountsDelivery Time: 3 - 5 days

£74.38 (£89.26 inc VAT)

£7.08/m2 (£8.50/m2 inc VAT)

show quantity discounts

Kingspan Styrozone H350R Flat Roof XPS Board is highly effective rigid insulation board made from extruded polystyrene core covered with smooth skin on both sides. It is especially designed for protected membrane flat roofs, but is also used in green roofs as a popular alternative to tradi..

£74.38 (£89.26 inc VAT)

£7.08/m2 (£8.50/m2 inc VAT)

show quantity discounts
= m2
other thicknesses
30mm Kingspan Styrozone N300R XPS Board (pack of 14)

30mm Kingspan Styrozone N300R XPS Board (pack of 14)

N300R 30mm - 10.50m2  show quantity discountsDelivery Time: 3 - 5 days

£62.66 (£75.19 inc VAT)

£5.97/m2 (£7.16/m2 inc VAT)

show quantity discounts

30mm Kingspan Styrozone N300R XPS Board is an insulation for inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring. They have high compressive strength, and a closed cell structure which resists the absorption of ground water and the passage of wate..

£62.66 (£75.19 inc VAT)

£5.97/m2 (£7.16/m2 inc VAT)

show quantity discounts
= m2
other thicknesses
30mm Sundolitt XPS300 Extruded Polystyrene Board (pack of 14)

30mm Sundolitt XPS300 Extruded Polystyrene Board (pack of 14)

1200x600mm - 10.08m2  show quantity discountsDelivery Time: 2 - 3 days

Guide Price: £58.12 (£69.74 inc VAT)

£5.77/m2 (£6.92/m2 inc VAT)

show quantity discounts

30mm Sundolitt XPS300 is an extremely durable thermal insulation board made of extruded polystyrene offering exceptional thermal performance and versatility. It is a lightweight board that is able to withstand extreme loads. Sundolitt XPS300 is highly water resistance, so can be stored and installed..

Guide Price: £58.12 (£69.74 inc VAT)

£5.77/m2 (£6.92/m2 inc VAT)

show quantity discounts
= m2
other thicknesses
50mm Cellecta Hexatherm XDRAiN Drainage Channel Inverted Roof Board

50mm Cellecta Hexatherm XDRAiN Drainage Channel Inverted Roof Board

600x1250mm - 0.75m2  Delivery Time: 2 - 4 days

50mm Cellecta Hexatherm XDRAiN is a high performance extruded polystyrene inverted thermal roof boards, featuring integrated drainage channels on their underside, which speeds up the shedding of rainwater from the roof, eliminating the need for a separating drainage mat, making them ideal for green ..

= m2
other thicknesses
50mm Cellecta Hexatherm XROOF 300L Thermal Roof Insulation Board

50mm Cellecta Hexatherm XROOF 300L Thermal Roof Insulation Board

600x1250mm - 0.75m2  Delivery Time: 2 - 4 days

50mm Cellecta Hexatherm XROOF 300L is an extruded polystyrene thermal insulation board designed specically for inverted roof applications where a high resistance to compression and water absorption is essential. XROOF roof insulation boards are ideal for a multitude of roofing requirements, inc..

= m2
other thicknesses
56mm Cellecta Hexatherm XMD Vertical Up-Stand Roof Board

56mm Cellecta Hexatherm XMD Vertical Up-Stand Roof Board

1200x2400mm - 2.88m2  Delivery Time: 2 - 4 days

56mm Cellecta Hexatherm XMD is a high performance extruded polystyrene thermal insulation board bonded to a 6mm thermal laminate facing, suitable for vertical upstands. It combines the benefits of high performance extruded polystyrene with a facing board to produce a composite thermal board to suit ..

= m2
other thicknesses
Kingspan Aquazone - Water Infiltration Reduction Membrane for Inverted Roofs

Kingspan Aquazone - Water Infiltration Reduction Membrane for Inverted Roofs

3m x 100m - 300m2  Delivery Time: 3 - 5 days

£441.00 (£529.20 inc VAT)

£1.47/m2 (£1.76/m2 inc VAT)

Kingspan Aquazone is a high performance non-woven polyethylene membrane suitable for use on inverted roofs finished with gravel ballast, green roof systems and concrete pavers on appropriate supports. Kingspan Aquazone can can dramatically minimise the cooling effect associated with rainwater f..

£441.00 (£529.20 inc VAT)

£1.47/m2 (£1.76/m2 inc VAT)

= m2
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