GE Lighting – Northampton

Re-coat steel roof sheets and treat cut edge corrosion

Roof area:
20,000 m2

Paint system:
Rustoleum Noxyde (20 year guarantee)

Time frame:
6 weeks

Our objective on this job was to re-coat a 20,000m2 roof and treat the laps for corrosion. The project was specified by Rustoleum. As MJJM are approved Rustoleum applicators and we have the infrastructure to take on a project of this size, we were award the contract.

Stage 1: Safety

The height of this roof was 35m, so safety procedures were paramount. A Haki staircase and guard-rails were erected, and the man-safe system was externally checked and signed off as being safe. MWEPS were positioned at ground level in case an emergency get-down was needed.

Stage 2: Cleaning

The existing coating was Plastasol. After carrying out a huge amount of adhesion tests to the existing Plastasol it was deemed to be in good condition and structurally sound, with the exception of the laps and sporadic rust spots. Stripping the existing plastisol with Ultra high pressure washing wasn’t required.

The roof had years of build up of moss, growth, contaminates etc. It was decided that a non-destructive wash using 3000psi pressure washers in combination with fungicide chemicals would be the most appropriate option.

Rustoleum fungicide chemicals were sprayed over the entire roof and left for 24 hours to have an affect on the thick growth. After which, several pressure washers would work back over the roof removing as mush growth as possible. This process was carried out several times in order to prepare a perfect substate for the Rustoleum Noxyde to adhere to.

Stage 3: Cut edge and lap treatment

As with many industrial roofs of this age the laps and the cut edge take the brunt of any corrosion. This is because when roof sheet are manufactured, the point where the cut is made is not protected, so bear metal is exposed, even on a brand new roof from day one.
To solve this common problem we removed the existing Plastersol and rust on and around the cut edges back to shiny metal substrate using mechanical sanders and grinders. Next we applied Rustoleum Noxyde red primmer, followed by a line of Rustoleum Elastofill Acrylic Jointing Compound. This jointing compound fills the gap in the overlap of the roof sheet stopping capillary action (stopping water moving in between the lap).

Stage 4: Spray protective roof coating

One day before spraying a final wash down of he roof was completed to remove any debris and mess. Rustoleum ND-14 was added to the water. ND-14 is an Alkaline degreaser.

The Rustoleum Noxyde had to applied in 2 coats achieving a total dry film thickness of 1000 microns. Airless spray guns were employed for this task. Airless spray has the power to pump through Rustoleum Noxyde which is very viscous at the correct flow rate and has the pressure to achieve a fan pattern that leaves a perfect finish.

Stage 5: Inspection and guarantee

After all works are complete Rustoleum representatives visit the site to inspect the quality of work for the final time. They thoroughly test many areas of the roof for a dry film thickness reading of 1000 microns. This was achieved successfully and a 20 year manufactures guarantee was issued to the client.