J Waterproofing

Contents

J2 ASPHALT COATINGS
J21 Mastic Asphalt Roofing/Insulation/Finishes
J22 Proprietary Roof Decking With Asphalt Finish
J3 LIQUID APPLIED COATINGS
J30 Liquid Applied Tanking/Damp Proofing
J31 Liquid Applied Waterproof Roof Coatings
J32 Sprayed Vapour Barriers
J33 In Situ Glass Reinforced Plastics
J4 FELT/FLEXIBLE SHEETS
J40 Flexible Sheet Tanking/Damp Proofing
J41 Built Up Felt Roof Coverings
J42 Single Layer Polymeric Roof Coverings
J44 Sheet Linings For Pools/Lakes/Waterways

J21 Mastic Asphalt Roofing/Insulation/Finishes

CONSIDER:
• Green Roof See J4
• Brown Roof See J4
• SUDS: Sustainable Urban Drainage Systems: Water stored on roof: See R10
• Foamed recycled glass thermal insulation, water and vapour resistant (though it does use bitumen).

J22 Proprietary Roof Decking With Asphalt Finish

CONSIDER:
• Green Roof See J4
• Brown Roof See J4
• SUDS: Sustainable Urban Drainage Systems: Water stored on roof: See R10
• Foamed recycled glass thermal insulation, water and vapour resistant (though it does use bitumen).

J3 Liquid Applied Coatings

ALERT:
• Many of the liquid applied coatings contain hazardous materials
- Paints, tins and residues are classed as Hazardous Waste.

J30 Liquid Applied Tanking/Damp Proofing

ALERT:
• Many of the liquid applied coatings contain hazardous materials.

J31 Liquid Applied Waterproof Roof Coatings

CONSIDER:
• Green Roof See J4.
• Brown Roof See J4.
• SUDS: Sustainable Urban Drainage Systems: Water stored on roof: See R10.

ALERT:
• Many of the liquid applied coatings contain hazardous materials.

J32 Sprayed Vapour Barriers

AVOID:
• Many are plastics (petrochemical derivative, non-renewable) or rubberised materials
• PVC See Z50
• Virgin plastics See Z50

J33 In Situ Glass Reinforced Plastics

AVOID:
• Many are plastics (petrochemical derivative, non-renewable) or rubberised materials
• PVC See Z50
• Virgin plastics See Z50

J4 Felt/Flexible Sheets

CONSIDER:
• GREEN ROOFS:
• An addition to roof drainage is to use inverted green roofs which store water on the roof within the soil and reservoir layer and plants themselves, taking some of the burden from the drainage systems in surge conditions.
• Due to the presence of trees, leaf clearance maintenance is an issue - but this is also the case for all water disposal systems, particularly guttering at Autumn time.
• Access and safety need to be provided
• Every roof and gutter should have a minimum of two outlets or an overflow
• The products are tried and tested extensively in the UK and mainland Europe
• See 'Materials - Green Roofs' for more information.

BROWN ROOFS/GRAVEL ROOFS:
• The choice to use gravel as an alternative can have its problems:
- Wind scour will drive gravel to edges and corners and once built up blow them over the parapets and then potentially towards the extensively glazed elevations
• Brown roofs are usually gravel, of all sizes, ideally extracted from the site. A covering can also be from crushed masonry of all sizes.
• Gravel is laid on a flat roofs (with perimeter upstands). The roof is designed to be similar to a green roof with the exception of it being relatively dry and free of soil and grass or other planting.
• Certain birds used to pebbly beaches see these brown roofs as potential nest sites and move in, bird droppings often containing seeds will establish themselves and soon birds, grasses and insects take over the roof.
• Insects live in the interstices of the gravel along with the droppings and other wind blow detritus
• The illustrations on the 'Black Redstarts' website show mixing other materials, like natural beach debris added into the roofscape, and including mounds of earth with grasses and sedum.
• They discourage mono-cultures, encourage mixing species if plants are added and use of multi species sedum, but most important is use of indigenous species to support indigenous insects and birds.

AVOID:
• Many are plastics (petrochemical derivative, non-renewable) or rubberised materials
• PVC See Z50
• Virgin plastics See Z50

J40 Flexible Sheet Tanking/Damp Proofing

CONSIDER:
• Clay powder and fabric carrier DPM there is at least 1 BBA Certified Clay DPM membrane.
• EPDM (Rubber) high natural content, there are 4-5 BBA Certified EPDM membranes.
• Crushed brick, block or stone as hardcore over site.
• Fine crushed glass as glass-sand blinding to hardcore.
• DPM below porous paving areas as catchments for rainwater harvesting and recycling.
• No DPM below porous paving areas for ground water replenishment as part of SUDS SUstainable Drainage Systems.

RECLAIM AND REUSE:
• Membranes laid without adhesive can be tailored to a new roof and reused.

AVOID:
• Many are plastics (petrochemical derivative, non-renewable) or rubberised materials.
• PVC See Z50.
• Virgin plastics See Z50.

J41 Built Up Felt Roof Coverings

CONSIDER:
• High performance elastomeric membranes are taking over some of their market share (longer design life)
• BBA Certified roofing membranes
• Green Roof See J4
• Brown Roof See J4
• SUDS: SUstainable Drainage Systems: Water stored on roof: See R10.

RECYCLE:
• Traditional 3 layer built up roofing laid in bitumen is brittle and difficult to reclaim for reuse but might be possible to reclaim to recycle.
• We're not aware of any company offering a take-back scheme, of construction waste nor demolition materials.
• At the CAT Centre of Alternative Technology they promote the idea of loo.se laying membranes, no adhesive or mechanical fixings and using ballast to hold it down against wind
• When they redevelop a building they dismantle it and reuse the roofing membrane by tailoring it to the new roof profiles.

AVOID:
• Low performance roofing felt systems.
• Short design life: BRE Digest suggest 20 years if designed and installed well.

J42 Single Layer Polymeric Roof Coverings

CONSIDER:
• TPO Thermoplastic Polyolefin in place of PVC (Sarnafil do a Polyolefin membrane too)
• EPDM (Rubber) is better having a high natural content
• There are 4-5 BBA Certified EPDM membranes
• There are other choices of materials
• Leaks are easily determined by electronic detection
• In addition to roof drainage use inverted green roofs which store water on the roof within the soil, reservoir layer and within the plants themselves. This helps by taking some of the burden from the drainage systems in surge conditions

REUSE:
• Loose laying and ballasting of a membrane means it can be reused more readily.
• We are not aware of take-back schemes.
• At the CAT Centre of Alternative Technology they promote the idea of loose laying membranes, no adhesive or mechanical fixings and using ballast to hold it down against wind. When they redevelop a building they dismantle it and reuse the roofing membrane by tailoring it to the new roof profiles.
Paola Sassi's papers and proposals are encouraging this approach.
• We are not aware of any products that contain recylates - this is probably because of the perceived risk of failure in using recycled materials in roofing membranes.

AVOID:
• PVC See Z50
• Virgin plastics See Z50
• Chlorinated Polyethylene See Z50

J44 Sheet Linings For Pools/Lakes/Waterways

CONSIDER:
• Natural swimming ponds.
• Puddled clay waterproof lining.
• Clay based DPM lining.
• Michael Littlewood a landscape architect and author of Landscape detailing books also promotes and designs natural swimming ponds where humans, frogs and other pond life share the same water .