Whilst many of our customers are highly knowledgeable when it comes to both practical and technical terminology. RKD products are designed for both Trade and DIY customers.

We have therefore provided a glossary of terms to assist in straightforward explanation of frequent words and phrases in common usage of products and processes when installing flat roofing kits and materials.

Terms below are in general alphabetical order please take note that explanations are within the context of flat roofing criteria only.

One Piece Membrane – Rubber Roofing, the provision of EPDM membrane in one complete sheet for robustness of waterproofing.


1.2mm Membrane – Rubber Roofing, denotes the thickness of the EPDM Membrane, most popular, allows maintenance or light foot traffic.


1.5mm Membrane – Rubber Roofing, denotes the thickness of the EPDM Membrane, heavier duty, allows foot traffic, green roofing.


450g – Fibreglass Roofing, denotes 450 grams per square metre, Chopped strand matting weight, used for roofs with light foot traffic only.


600g – Fibreglass Roofing, denotes 600 grams per square metre, Chopped strand matting weight, used for roofs with moderate foot traffic.


Acetone – a colourless volatile liquid ketone made by oxidizing isopropanol, used as an organic solvent and synthetic reagent.


Asphalt – a mixture of dark bituminous pitch with sand or gravel, used for surfacing roads, flooring, roofing, etc.


Bandage – Fibreglass Roofing – strip of chopped strand matt, used for waterproofing edge trims and trim joints, overlaps etc.


Bank Transfer – RKD – payment for product straight to our bank account, rather than merchant provider, product is processed when funds clear.


BBA Certificate – BBA Certificates are an independent statement of a product’s fitness for its intended purpose by approved body.


Bitumen – a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation. Used for roads and roofing.


Bonding – Rubber Roofing – Bonding adhesive or contact adhesive which surface joins 2 surfaces together creating a stronger adherence.


Breather Vent – Roofing – an opening that allows air to pass out of or into a confined space.


Catalyst – Fibreglass Roofing – often called hardener, when mixed with resin and topcoat in measured quantities allows them to cure (go hard).


Catalyst Addition – Fibreglass Roofing – Catalyst addition to resin and topcoat is precisely measured and varies dependent upon temperature.


Classic – Fibreglass Roofing – This is our standard range of fibreglass roofing kits, uses blended resin – our most frequently purchased kit.


ClassicBond – Rubber Roofing – Manufacturer/Brand – ClassicBond® EPDM Is the original EPDM roofing system first used in the 1960’s.


ClassicLiquid – ClassicLiquid system provides a rapid curing polyurethane liquid membrane designed for overlaying existing roofing systems.


Clout Nails – Flat headed nails, sometimes called felt nails, galvanised, corrosion resistant.


Consolidation – Fibreglass Roofing – the process of consolidating Chopped strand matting within the resin basecoat.


Contact Adhesive – Rubber Roofing – Contact or Bonding adhesive which surface joins 2 surfaces together creating a stronger adherence.


Corner Patches – Rubber Roofing – Patch to seal where rubber membrane meets internal or external corners.


Cover Tape – Rubber Roofing – EPDM Tape is for completing any awkward and hard to-do joins.


CSM – Chopped Strand Fibreglass Matting.


Cure – Fibreglass Roofing – Means ‘go hard’ – the reaction of catalyst with resin and topcoat enables this.


Deck – The wooden surface to which rubber or fibreglass roofing is installed – RKD recommend OSB3 18mm.


Deluxe – Fibreglass Roofing – our premium range of fibreglass kits, Lloyds certified, 100% pure resin – very high quality.


Distillates – a liquid product condensed from vapor during distillation. – something concentrated or extracted as if by distilling.


Dormer Roof – a roofed structure, often containing a window, that projects vertically beyond the plane of a pitched roof.


Double Layer 450g – Fibreglass Roofing, denotes 450 grams per square metre, Chopped strand matting weight, Two layers – used for roofs with heavy foot traffic such as walkways or balconies.


Drip Trim – also called gutter edge trim – trim to seal the roof enabling waterflow off the roof to a gutter.


Edge Trims – preformed trims fitted to the roof edges to both seal and waterproof directing water run off.


EPDM – Rubber Roofing – ethylene propylene diene monomer – a mix of chemicals – simply put, rubber roofing membrane.


Exotherm – Exothermic reactions are reactions or processes that release energy, a compound that gives off heat during its formation.


Expansion Joint – Fibreglass roofing – Used in fibreglass roofing over 50m2 to enable expansion/contraction in hot or cold conditions,


Extension Roof – Nominally a roof which is attached on one or more sides to a property.


FAQ – well known, stands for Frequently Asked Question.


Fascia Board – used to secure the gutters to the roof and keep them in place. Blocks water from penetrating the roof deck and into the attic/home. Increases curb appeal by covering the open/rough ends of the rafters.


Feathered Edge – Fibreglass Roofing CSM has one plain straight edge and one feathered edge – made for joining one strip to another.


Felt Nails – Flat headed nails, sometimes called clout nails, galvanised, corrosion resistant.


Fibreglass – a textile fabric made from woven glass filaments.


Fibreglass Roof Kit – RKD grouping of the primary products used to install a fibreglass roof – Resin, CSM, Topcoat, Catalyst & Bandage.


Fire Rating – statutory body designation of fire retardant capability eg EXT.F.AB according to BS476 part 3:2004. (our fire retardant kit rating).


Fire Retardant – having the ability or tendency to slow up or halt the spread of fire.


Flat Flashing – Fibreglass Roofing – The flat flashing trim is mainly used at the intersection of a pitched and flat roof.


Flexitec – GRP Overlay system from Restec.


G4 Sealer – mainly used to seal concrete to allow fibreglass adhesion to a concrete slab or pond surrounds/base.


Garden Room – very popular today, can be an office, man-cave, outbuilding – normally a detached outbuilding.


GDPR – General Data Protection Regulation – law for the privacy, treatment and management of personal data.


Geotextile Fleece – a 200gsm Non-woven Geotextile Fleece Underlay – used for membrane protection from sharps.


Green Roof – A green roof is a layer of vegetation planted over a waterproofing system that is installed on top of a flat or slightly–sloped roof.


GRP – Glass Reinforced Plastic.


GRP Overlay System – a system which combines the versatility of liquid with the strength of fibreglass – used to overlay an insitu roof.


Hardener – Fibreglass Roofing – often called catalyst, when mixed with resin and topcoat in measured quantities allows them to cure (go hard).


Horizontal Drain – preformed drainage element to allow water run off through an upstand or parapet wall.


Internal Drain – where drainage occurs from the roof structure down through the deck and timber roof structure.


Kerb Trim – Rubber roofing – an edge trim with a raised element to direct water to the drip or gutter edge.


KG, kg – Abbreviation for Kilograms.


Laminating – Fibreglass Roofing – overlay (a flat surface) with a layer of catalysed resin.


Leadmate – product – used for securing flashing trim into a groove ground into the mortar of a house wall.


Leaf Grate – used in combination with an internal or horizontal drain to prevent blockage with debris such as leaf fall.


Life Expectancy – RKD – simply the longevity of product viability gained through experience, time and product capability.


Liquid Roof Kit – a rapid curing polyurethane liquid membrane designed for overlaying existing roofing systems.


Lloyds Approved – Certification – product conforms to recognised marine industry quality standards, International Conventions.


Ltr – Abbreviation for Litres.


m2 – Abbreviation for metres squared or square metres.


Man-cave – nominally a detached outbuilding, office, den or high class shed.


Membrane – Rubber Roofing – a thin pliable sheet of material forming a barrier or lining.


Mitre Joint – a joint made between two pieces of material at an angle of 90°.


National Delivery Profile – RKD deliver to the UK mainland, including some offshore islands (we do not deliver to N. Ireland.


Open Ended Corner – where two trims meet at right angles one overlapping the other leaving an open end to be closed with bandage/ resin.


Orangery – a home extension with a glass roof typically covering less than 75% of the overall roof area.


Order Signature – the signature upon receipt of your order via the courier – this denotes your acceptance of the product as ordered.


OSB – Oriented strand board – structural – recommended for use in roof decking – comes in std 8 x 4 sheets or T&G 8 x 2 sheets.


OSB T&G – Oriented strand board with tongue and groove edging which joins sheets together, giving expansion elements and deck sealing.


Outbuilding – can be detached or adjoining another property, man-cave, shed, garden room etc.


Overboard – Roofing – the process of laying a new roof deck on top of an original deck or roof. Or a new layer over boarded decking over an original.


Overlay – Roofing – the installation of a new roof over an original or in-situ roof.


Paddle Roller – called bubble buster or consolidation roller – tool used to consolidate Chpped strand matting within a resin base coat layer.


Parapet – Upstand or small wall surrounding a roof area on one or more sides.


Payment Options – RKD orders can be paid for securely by Bank Transfer, Paypal or Stripe payment platform.


Paypal – Company offering secure method for online payment.


PDF – a file format for capturing and sending electronic documents.


Penny Roller – Rubber Roofing – an ideal tool for compressing membrane on any corners. overlaps and when using tapes etc.


Pipe Boot – Rubber Roofing – Used to create a waterproof seal where pipes come through the roof deck.


Platinum – Fibreglass Roofing – Our range of Fire Retardant Fibreglass Roof Kits.


Primer – Liquid and Grp overlay Roofing – rapid-curing, cold applied liquid applied before application of overlay material.


Primer – Rubber Roofing – used to bond different accessories to your Rubber membrane, for example tapes and pipe boots.I t is also used when constructing internal and external upstand corners.


PU – Polyurethane.


Raised Edge Trim – Fibreglass Roofing – an edge trim with a raised element to direct water to the drip or gutter edge.


Restec – manufacturer of Flexitec 2020 GRP overlay system.


Right Angle Trim – Fibreglass roofing – trim used to protect and reinforce 90° angles in Fibreglass roofing – upstands steps etc.


RKD – That’s us – Roofing Kits Direct


Roof Lantern – Skylights and roof lanterns are both often referred to as roof lights. An umbrella term for any window positioned atop a flat or pitched roof.


Roofing Resin – polyester resin which is suitable for Fibreglass Roof repairs and builds.


Rubber Roof Kit – Membrane and adhesives appropriate for epdm roofing installation.


Russ Tape – Rubber Roofing – The base ties mechanically fix the membrane to the roof deck where the membrane turns UP through an angle change. e.g. Wall upstand – used with plate fixings and prevents any shrinkage affects.


Seam Tape – Rubber Roofing – Seam Tape is useful when joining sheets of EPDM (especially in more complex roof shapes where 1 piece epdm is not pragmatic.


Seam Roller – Rubber Roofing – tool to install uncured flashing tapes, splice tapes and compressing membrane into corners angle etc.


Shed – Outbuilding – from the garden shed to the garden room office


Simulated Flashing Trim – Fibreglass Roofing – as the title, a GRP trim, used instead of lead, to flash over the wall fillet trim to secure waterproofing where a roof deck meets house wall or upstand.


Skylight – Sky lights and roof lanterns are both often referred to as roof lights. An umbrella term for any window positioned atop a flat or pitched roof.


Split Delivery – Many of our deliveries contain multiple components which can be delivered separately by one courier or may be issued via two or more couriers.


SQM, sqm – Abbreviation for metres squared or square metres.


Stripe – A secure online transaction payment platform.


Styrene Emission – Fibreglass roofing – low styrene emission resin. means a resin with a maximum emission rate of 20 grams of styrene per square metre of resin per half hour at 23°C, …


Substrate – The composition or make up of layers underneath the roof installation.


Sure Edge – manufacturer/Brand of Rubber Roofing Edge trims.


Temperature – obvious but when measuring temperature affecting roof installation remember there is ambient temperature and roof deck temperature which can affect curing in very hot or cold conditions.


Thixotropic – Thixotropy is a time-dependent shear thinning property. resins that are thick or viscous under static conditions will flow (become thinner, less viscous) when installing and consolidating.


Tool Kit – Rubber or fibreglass – multiple sizes – amalgam of suitable products to assist in roof kit installation.


Topcoat – Fibreglass Roofing – the smooth, coloured, surface coating of a fibreglass roof which actually bonds to the resin basecoat.


TriCure – Products base of our Classic fibreglass roofing kits, manufactured by Tricel Composites.


TriRoof – Products base of our Deluxe and Premium fibreglass roofing kits, manufactured by Tricel Composites.


Uncured Tape – Rubber roofing – tape which requires primer to adhere or patch corners or membrane.


Upstand – A vertical projection occurring on or around a roof – eg Parapet.


Wall Fillet Trim – Fibreglass Roofing – Trim used where roof deck meets an adjoining wall or parapet.


Warm Roof – A roof where insulation is attached to the roof structure – often meaning a layer of boards to which insulation is attached and a 2nd layer on top to which roof kit is installed.


WBA – Rubber Roofing – Water Based adhesive.


Wet Out – the process of application of resin and matt forming the base layer of a fibreglass roof.


Wish List – capability of website users to save products or kits placed into the shopping basket to purchase at a later date.