Concrete Base

We offer a Nationwide base laying service. Our ground-working teams can remove old garages, including asbestos, carry out excavation and lay your new concrete base.

In order to obtain a quote for these works, please contact us on 0800 043 6954 or email [email protected]

Concrete Base Design

Your concrete base needs to be designed properly to be strong enough not to crack or sink over the lifetime of your garage. Your garage base should be designed to suit the soil on your site. For instance, if the soil is clay, with the likelihood of movement in the future, you will need to reinforce it, and probably make the raft thicker. You should thicken the edges of the base to a depth to suit the ground conditions. The thickness of the concrete in the base will also depend on the soil conditions.

The concrete mix design should be suitable for a garage base – speak to your supplier and tell them what the concrete is intended for so they can provide the correct mix. A minimum concrete thickness of 100mm (4”) is normally recommended, laid over at least the same thickness of well compacted clean hardcore. The hardcore should be “blinded” with sand if you are going to lay a damp proof membrane (dpm), normally 1000g polythene sheet. Steel reinforcement mesh will further strengthen your base but isn’t essential.

The concrete base should be Square. When setting out your base, make sure that the shuttering is square and that the external dimensions are ideally 75mm (2”) larger (each side and front and rear) than the size of the building you have bought. If in any doubt, seek advice and confirmation of the size of your building from either the Garage manufacturer or White Rose Buildings. To make sure your base is square, measure the diagonals AD and BC – they should be the same. If not, adjust your shuttering until they are – your base will then be Square.

The concrete base should be Level. There must be no slope from side to side, back to front or front to back. If the base isn’t level, the installers may not be able to build your garage properly, and the 10 year guarantee may be invalidated if they do build it.

Due to gradients / ground levels your site, if the concrete base is over 12” (300mm) higher than the general lay of the land then a retaining wall of some description will be required. We recommend a block or brick wall as the best option. This will work to retain the backfill and concrete in the new concrete base.

If the base is too far out of level, they may have to abort the delivery, and it will cost up to 20% of the value of the garage as a redelivery charge, and potentially delay redelivery of your building for at least 2-3 weeks.

Finally, your concrete base should be Positioned properly. Don’t forget that the up and over door can project up to 1220mm (4ft) in front of the building when it is being opened, so position the base so the door doesn’t foul a wall or other building when you open it. A standard 1981mm (6’6”) up and over door projects 910mm (3ft).Please LOOK UP! Trees, buildings etc can overhang, branches and gutters can affect the positioning, just because it fits on the base, doesn’t mean it will fit at eaves height! Don’t position the building too close to other buildings or walls, as this can form a water trap – always specify gutters on your garage to minimise the potential for water leaking into your garage. Allow for guttering on your building if you order it – add in 150mm each side (Apex) or 125mm to the length (Pent) for guttering.

We want you to get this critical part of the contract right – Online Garages offer a base laying or refurbishing service but can also offer advice before you get started, so please contact us on 0800 043 6954 or email [email protected] for more information.

If you are using a local builder to carry out the base works for you, please give him this before he starts work.