Grafo Products Ltd
Grafo Products Ltd
Hardened Aircraft Shelters

Material Specification of the internal and external treatment of Hardened Aircraft Shelters

The following photograph below shows the Hardened aircraft shelter before any treatment has taken place, the photograph was taken on 12/2/10 and shows the pools of water formed from condensation running down the shelter sides.



This photograph show where the condensation runs down the sides and also where the shelters tend to leak as seen by the calcium deposits around the bolts.



This photograph shows a treated Shelter coated with Grafo-therm 25 years after application and still performs today as when first applied in 1985.



This photograph shows how the Grafo-therm coating has stopped the calcium deposits entering the shelter and through the seams to seal the leaks. The increase in light reflection gained by Grafo-therm's surface is very noticeable as is the decrease in reverberating sound within the shelter.



Further photographs of a Grafo-therm coated shelter




Our specification for the internal treatment of the Hardened aircraft shelters is as follows: Firstly we apply an environmentally friendly grease and oil remover to enable us to remove the sooty type of film on the galvanises sections, this can be over a centimetre thick depending on which type of aircraft has used the shelter. Once the grease/oil remover has emulsified the film, we would then pressure wash the surface until it is clean enough to enable good adhesion of the Grafo-therm coating.

Once the cleaned surface has dried we would then treat the rust on the bolt heads with Grafo Penetrust which is a rust stabilising primer.

We would then apply a 1.5mm average thickness of Grafo-therm anti condensation coating to all galvanised surfaces including the rear wall, all coating would stop 150mm from the floor.

The above specification has been tried and shown to perform exceptionally well for over 24 years in nearly 40 hardened aircraft shelters across the UK and needs no maintenance.

Our specification for the external coating of the hardened aircraft shelters would be as follows; firstly we would clean the stain residue from the concrete using high pressure washers, we would then remove any loose of friable material from the horizontal seam where the formed concrete sides join the floated top section of the shelter. Here we may need to use a scrabbler, as in our experience there can be quite a lot of cracking in this area.

We would then fill the cracks above 5mm in width with our Grafo-flexgrout which is a highly flexible grouting with excellent adhesion to concrete.

Once the concrete has dried from the pressure washing we would seal all concrete surfaces with Grafo-seal this gives the Grafo-flexicoat an ideal surface to adhere to.

When the Grafo-seal has dried we would then apply Grafo-flexcoat to all the cracks over 2-5mm in width, then apply a fibreglass tape over the top of the wet coating and press in, this reinforces the coating in areas that are known to move.

The shelter is now ready for 2-3 coats of Grafo-flexcoat to al concret surfaces. This is applied by roller to the following thicknessís on the top section 7m either side of the central vents we would apply a 1.0mm to 1,2mm thickness and on the sides we would apply a 0,8mm to 1,0mm thickness.

The above specifications has been tried and shown to perform well enough though we would advise that a 5 yearly maintenance survey be carried out by ourselves.

The photographs shown were all taken on 12/2/10 and show the Grafo-therm coated shelter 25 years after application onto hardened aircraft shelter 3055 at the old RAF Alconbury site. The external photographs are from the old RAF Woodbridge shelter number 1605 and is shown after 23 years from application, due to how well the specification has worked and is still working we are sure you would agree that this specification has proven itself.

The external coating conformed with the Thermal and infra red and light reflective requirements of any coating to be used on these shelters at the time of application.

These photographs show the external concrete finish of the Shelter they were originally coated with a type of stain that tones the colour of the concrete down, this leaves a very hard to remove residue that becomes quite slippery when wet.



This photograph shows a Shelter coated with Grafo Flexcoat over 23 years ago, the moss and lichen shown in the photograph is easiy removed to reveal the coating beneath still in good condition.


This photograph shows the side elevation showing how well the Grafo Flexcoat is performing.


This photograph shows a close p of the coating, the dark spots are air holes and are fully coated.





Grafo Products Ltd, The Old Goods Depot, St Johns Rd, Saxmundham, Suffolk, IP17 1BE
Tel 01728 603664 Fax 01986 872850 email grafoproducts@btinternet.com