The World War Two hangar had sat unused for several years and was being repurposed. As part of this the following issues required addressing to allow its continued operation;
We proposed a range of solutions tailored to each particular challenge. Some of the other issues we had to consider were that the existing steel coatings were found to be lead containing and that the roof shingles contained asbestos.
Initially the perimeter gutters were cleared of moss by operatives Category B Asbestos trained due to the risk of the moss being contaminated with Asbestos. The moss was double bagged and removed to our on site asbestos skip.
Once cleared of moss the gutters were cleaned by method of pressure washing. Any corroded areas were prepared to ST2 as per ISO8501-1 and primed using Corroless EPF – our rust stabilising primer which contains a mined pigment that converts corrosion present to stable iron oxides such as magnetite.
Part of the cause of water ingress we identified was that detailing around rain water outlets and lead flashings was particularly poor. These were first detailed using a polyurethane jointing compound as a first layer of waterproofing.
An initial bonding layer of Remmers MB2K was then applied throughout the gutters by method of slurry brush and trowel. Areas liable to movement were then reinforced using Remmers VF120 bandage embedded within Remmers MB2K.
Two further coats of Remmers MB2K were then applied throughout the gutter as per the manufacturers recommendations. The properties which made Remmers MB2K particularly suitable for this waterproofing project were its broad application window and flexibility once cured.
Remmers MB2K does not have any dew point or humidity restrictions which was essential given the works took place from winter through to spring.
The joints in the valley gutters were treated internally using the same system. The reason for this was that the roof of the building was deemed to fragile to allow access to the valley gutters externally. Whilst we could not guarantee that this would be effective, Remmers MB2K is also used as an internal tanking system – displaying the phenomenal versatility of this waterproofing system.
The external steelwork coatings were exhibiting some localised perforations and approximately 5% coating breakdown, mostly focused on panel edges. During our initial site survey we performed adhesion tests to determine if the adhesion was sufficient for overcoating, which it was found to be.
The existing coatings were prepared to WA1 as per ISO8501-4 by method of high pressure water jetting. Any exposed steel was prepared to ST2 as per ISO8501-1 and transitions to existing coatings feather edged by means of sanding using vacuum controlled sanders and H type vacuums due to the presence of lead containing coatings.
As part of our standard protective coating quality assurance the prepared surfaces were tested for soluble salts – if left if place above permitted levels this can draw moisture through the coating film and cause osmotic blistering and premature corrosion. A climatic monitoring regime was instigated in order to ensure the correct climatic conditions for coating applied – ensuring the correct climatic conditions when applying protective coatings is essential to ensure correct adhesion and anti corrosion performance.
Once prepared any corroded areas were primed using Corroless EPF rust stabilising epoxy primer as mentioned earlier. Where perforations were present these were sealed by bonding in place galvanized steel plates with a thixotropic epoxy adhesive – this avoided the need for cutting and welding lead containing paints, which would produce toxic fumes.
Rustoeum Noxyde was then applied in two coats of contrasting colour at a coverage rate of 0.4Kg/m2 per coat – the rate required for optimum corrosion protection. Rustoleum Noxyde is certified to give 15 years performance even in the very demanding C5 corrosion environments as per ISO 12944.
Rustoleum Noxyde also offers excellent adhesion to a variety of substrates, including aged coatings. Rustoleum offers excellent edge retention, helping to prevent corrosion in areas where previously seen. This made it a perfect protective coating for this application.
Finally the external protective coating works were completed by the application of Rustoleum Metal Cladding Top Coat in the colour specified by the client.
For the building internals we initially removed the flaking and water damage coatings by method of high pressure water jetting. Any steelwork was prepared to the same standard as per the building externals.
Once prepared and dry we again applied Rustoleum Noxyde by method of airless spray. The benefits Noxyde offers when coating concrete and masonry is that it will not flake or peel like normal emulsion type materials, providing an extremely durable, crack bridging and long lasting aesthetically pleasing coating.
The painting of the walls significantly improved the light levels within the hangar, making a much improved working environment for its new use.
