Concrete Garages

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Concrete Base Requirements

Our Concrete Garages should only be erected upon a permanent concrete base of suitable thickness. A minimum of 4 inch thickness is recommended throughout. The base should be flat, level and square, and at least 6 inch longer and 6 inch wider than the external dimensions of the garage to be supplied.


The ground surrounding the base should be lower than the base. If not, water will rest on the base and break through the sand and cement fillet and leak into your building. If the driveway slopes down towards the front of your building, you must put in a gulley to take any surface water away. We cannot guarantee the performance of your building unless a gulley has been fitted.

3 4 5 triangleIn order to check that your base will be laid square, measure out a 3-4-5 triangle as per adjacent sketch before securing your timber shutters. 


corner to cornerIn order to give your timbers a final check prior to concreting, measure the diagonals which should be equal. We would also advise you to use a reputable ready-mix concrete company who will also be able to tell you the amount of concrete required.  

gappicIf you are close to an existing building or boundary wall, make sure that you allow for the overhang of the roof, i.e., flat roof garages 6 inch (150mm) on front and rear and 3 inch (75mm) both sides, apex roof 6 inch (150mm) front, rear and both sides. This does not include gutter width. 


the baseAfter your garage has been erected we strongly recommend that a sand & cement fillet be placed on the base to panel joint all around the inside (not outside) of the building to avoid ingress of water. We recommend a 3 part building sand to 1 part cement with Unibond (PVA) added to the mix.

If the base slopes from side to side, e.g. left to right, there will be problems sealing the end wall of the garage, fixing the roof, and the door will not fit evenly at the bottom when it shuts. The Base must be FLAT - if it has bumps in it the panels won’t join up properly or the roof won’t fit. The base must not slope or the panel bolt holes will not line up and the roof may leak.

If you live in the Yorkshire area, we provide a free site survey, call us for details.

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