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What is the Best Flat Roofing Sealant?

The age-old question, "What is the best flat roofing sealant?"

This would depend on a variety of factors, firstly there is not a one product fits all – due to the complexity of flat roofing products on the marketplace today ranging from basic bitumen, asphalt, liquid, rubber, GRP, single-ply and more.

Acrylic Coatings

Acrylic coatings have been around since the 1970’s and are a great sealant for asphalt/felt roofs, if cracks are evident then they will need to be bridged with a scrim/mesh/polyester fleece.

This not only binds the crack but will stop the thermal changes of this defect to open and close.

Some acrylic coatings come with tiny portions of chop stranded mat already mixed into the product and can seal the roof with cracks up to 3mm girth.

RIW/LAC Coatings

Riw or lac (liquid asphaltic coating) coating is a cold applied bitumen coating , this can be applied to seal roof junctions but is typically used as a DPM (Damp Proof Membrane) below ground level-riw coating is UV resistant and can also be used on concrete /brick work and when bitumen primed is tough and very durable , this can seal asphalt and felt systems  as well.

EPDM Liquid Rubber

EPDM liquid rubber is a 2-part system, catalyst is added to accelerate the drying time, once applied it can waterproof immediately and within hotter temperatures this will further accelerate the process, the top layer will film over and is highly elastic with great stock memory.

The EPDM liquid will self-level and can also be touched up with excess coats should this be required.

EPDM liquids are suitable for nearly all flat roofing products and are sold widely.

Pu Coatings

Pu coating as a sealant or polyurethane can be transformed into a permanent liquid waterproof sealant, the system is strong and can completely waterproof most fabrics.

The life expectancy of this product is 25 years is self-terminating and is suitable for single-ply or repair purposes as bitumen-based products will lead into the single-ply membrane and break the surface layer down.

With flat roof sealants improving with age, some emulsion coatings such as Karnak can be applied in wet conditions.

The crack/split can be covered, and a patch repair is achieved instantly on most surfaces.

The coating is low odour and has a heavy paint consistency and is also non-fibred, giving this product excellent protection against the elements.

GRP Flat Roofing Sealant

Our final product or roof sealer is GRP, this is ‘glass reinforced plastic’.

GRP is different to the conventional thermoplastics that are commonly used in everyday items.

Today GRP is far superior as a sealant than those in the past, todays is durable, flexible, and lightweight along with thicker matting and resin bindness, it is a very hard-wearing product and great repair system to many products.

If you need any more information or advice about choosing the best flat roofing sealant for a specific project, Southern Liquid Systems would be delighted to help you. Just call us on 0207 7818153 and one of our team will be happy to help you.