01 — Single ply in North East EnglandSingle ply roofing across North East England.
Evenii installs, replaces and repairs single ply membrane roofing — TPO and PVC systems — on commercial and industrial flat roofs across North East England. Single ply is one of the most widely specified flat roofing systems for larger commercial buildings: a factory-manufactured thermoplastic membrane, mechanically fixed or adhered over insulation, with welded seams and detailed terminations.
The work covers new-build single ply installations, strip-and-replace of failed flat roofing, overlay of existing roofs where the survey supports it, insulation upgrades within the same works, and repair or remedial work to existing single ply membranes installed by others. Each project runs through the same route: survey, written specification, programme, installation and documented sign-off.
The service area is the core Evenii geography — County Durham, Tyne and Wear, Teesside and North Yorkshire — worked from the base at Inkerman, Tow Law, Bishop Auckland, DL13 4HG. That covers commercial and industrial buildings in Durham, Newcastle, Gateshead, Sunderland, Middlesbrough, Stockton, Darlington and the industrial estates between them.
Single ply buyers are usually facilities managers, building surveyors, main contractors and public sector estates teams. They need a contractor who can talk about membrane type, fixing method, wind uplift, insulation, drainage and warranty routes in the same language the specification is written in — and who is based in the region the building stands in.
02 — Specification before productWhy specification-led single ply matters.
Single ply roofs fail at the specification stage more often than at the installation stage. A membrane that suits one building can be wrong for the one next door. The specification has to answer a series of questions before any material is ordered, and Evenii answers them from the survey, not from a preferred product.
Membrane choice comes first: TPO and PVC behave differently in chemical exposure, weldability, colour retention and compatibility with existing materials. Fixing method comes next — mechanically fixed systems suit most industrial decks and profiled metal substrates, whilst adhered systems suit roofs where fixings cannot penetrate the deck or where aesthetics and wind performance point that way.
Substrate condition determines whether an overlay is even possible. A survey establishes deck type and condition, moisture trapped in the existing build-up, insulation performance against current Building Regulations, and the position of falls and outlets. Drainage that worked for the original roof may not work once the build-up height changes.
Wind uplift calculation matters more in North East England than in much of the country. Exposed industrial estates, coastal sites and elevated ground all push up the fixing density the calculation demands — corner and perimeter zones need more fixings than the field of the roof, and the manufacturer's warranty depends on the calculation being done and followed.
Manufacturer warranty requirements shape all of it. Single ply warranties are conditional: approved installers, approved details, the specified fixing pattern, and inspection or completion records the manufacturer accepts. Evenii builds the warranty route into the specification at the start, so the client is not chasing paperwork after handover.
03 — From survey to sign-offHow a single ply project works.
Evenii runs single ply projects through a controlled route: survey, specification, programme, installation and sign-off. The client gets a written record of what was found, what was specified, what was installed and what evidence supports completion and warranty.
01
Survey within 5 working days
Deck type and condition, existing build-up, moisture, insulation, falls, outlets, penetrations, edge conditions, access and wind exposure. Recorded with photographs.
02
Specification
Membrane type — TPO or PVC — fixing method, insulation, tapered schemes where falls need correcting, detailing and the warranty route. Issued in writing before order.
03
Programme
Sequencing, access control, weather-tightness between shifts, material delivery and crane or hoist planning. Sits inside main contractor build programmes where relevant.
04
Installation
Qualified tradespeople installing to the confirmed specification and the manufacturer's requirements — welded seams, fixing pattern, detailing. No unrecorded scope drift.
05
Sign-off
Final inspection, photographs, seam checks, snagging where required, written confirmation. Warranted work and signed-off completion records for the client file.
A typical roof survey is completed within five working days where access, weather and site availability permit. On single ply work the survey stage carries real weight — the difference between a sound overlay and a strip-and-replace, or between a mechanically fixed and an adhered system, is decided by what the survey finds, not by what is cheapest to quote.
04 — Membranes & systemsMembranes and systems Evenii specifies.
TPO and PVC are the two single ply membranes Evenii installs most, but a survey sometimes points elsewhere. The right system depends on the substrate, roof use, exposure, chemical environment, budget and the warranty the client needs — and an honest specification says so when single ply is not the answer.
TPO membrane
Thermoplastic polyolefin single ply, hot-air welded, typically mechanically fixed over insulation on commercial and industrial decks. Plasticiser-free, weldable throughout its service life and widely specified for larger industrial roof areas where a manufacturer-backed system is required.
Industrial · large area · mechanically fixedPVC membrane
The longest-established single ply membrane, hot-air welded, available in mechanically fixed and adhered systems. Strong detailing flexibility and a wide range of approved accessories — often specified on roofs with complex penetrations, plant or visible elevations.
Commercial · detailed roofs · adhered or fixedWhere EPDM suits better
EPDM rubber suits smaller flat roofs, ancillary buildings and refurbishments where seams can be minimised and a welded thermoplastic system is more than the project needs. Evenii specifies it where the survey supports it rather than forcing a single ply answer.
Smaller roofs · ancillary · refurbishmentWhere liquid-applied suits better
Liquid-applied waterproofing suits complex details, roofs crowded with plant and penetrations, and overlays where removing the existing build-up is impractical. On some buildings it is the correct specification and single ply is not.
Complex details · overlays · plant-heavy roofsDetailing — where single ply roofs are won or lost
Upstands, penetrations, rooflights, outlets, edge trims and terminations decide whether a single ply roof performs for its service life. Evenii details each of them to the manufacturer's approved method — pre-formed corners, welded flashings, mechanically terminated upstands — and adds walkway pads where plant access will otherwise wear the membrane. Detailing is priced and specified up front, never treated as an extra.
Upstands · penetrations · outlets · edge trims · walkway padsAccreditations and compliance.
Evenii holds CHAS Advanced, NFRC membership and Reset Compliance. These are the credentials single ply buyers check first: CHAS Advanced supports health and safety pre-qualification, NFRC membership verifies roofing competence through the national trade body, and Reset Compliance supports contractor approval processes. ISO 9001:2015 and ISO 14001 are currently undergoing certification.
Single ply work on commercial and industrial buildings routinely requires RAMS, CDM 2015 compliance, hot works controls for welding equipment, edge protection and access planning, waste transfer documentation and insurance evidence. Evenii provides the pre-start pack the client process requires and keeps the paperwork current through the works.
Warranty documentation is part of compliance, not an afterthought. The completion file for a single ply project includes the specification, installation records, photographs, any manufacturer inspection reports and the warranty itself — the evidence a facilities manager or building owner needs on file for the life of the roof.
CHAS Advanced, NFRC and Reset Compliance — verify credentials
06 — Sectors & building typesSectors and buildings suited to single ply.
Single ply suits large, regular flat roofs — which is why it dominates industrial units, warehouses, schools, healthcare buildings, offices and retail. Industrial clients need programme discipline and minimal disruption to operations below. Schools need term-time planning and safeguarding awareness. NHS estates need controlled access and method statements. Housing associations and property managers need stock-level reporting and a maintenance route once the roof is on. Evenii plans single ply work around the building staying in use — occupied premises are the norm, not the exception.
