Frequently Asked Questions

Your precast concrete garage requires a concrete raft base, designed to suit your local ground conditions. It needs to be Strong enough, be Pent, Square and Level.

One of our local agents will be able to give you advice, arranging a site meeting as necessary to discuss your detailed requirements. Please call our team at Head Office if you need any further help or assistance. Our leaflet, The Concrete Garage Base, will answer most questions in detail – please make sure that you give a copy to whoever you employ to build your base.

No, we cannot build a concrete sectional garage on anything other than a concrete raft base. Any movement in the base will invalidate our 10 year guarantee. We will not build on tarmac or gravel, only on a properly specified concrete base.
Unfortunately, not necessarily. The base must still be strong enough, be Pent, Square and Level, and fit for purpose. Bases laid for old timber, corrugated iron or timber framed asbestos garage are normally not suitable, as the weight on these garages did not require a substantial base. Your new garage will typically weigh between 3 and 4 tons.

An existing concrete base would need to be surveyed to ensure it met our requirements. An existing base can be “skimmed” if basically sound, again your local agent or builder can advise.

If you are only putting our garage on the base, simply 150mm (3”) larger all round, so you base should be 300mm (6”) longer and wider than the external dimensions of the garage you have chosen.

If you have chosen TrueBrick front posts, you will need to make extra allowance for the brick thickness, so you should allow xx mm (yy”) on the length of the base. For garage sizes, lengths and widths, these garage size tables will help you.

Sizes for Pent and Apex garages


From 8’3″ to 30’3″ in 2’0″ increments as standard.
Special widths are available; please contact us to discuss the options.


From 8’1″ to whatever length you want!! In 2’0″ increments as standard.
Special lengths are available; please contact us to discuss the options.


From 6’6″ in 6″ increments as standard (7’0″, 7’6″, 8’0″, 8’6″, 9’0″ etc.) up to 16ft!!
Special heights are available; please contact us to discuss the options.

Simply put a plastic damp proof membrane (dpm) in the base when casting it. 1000g plastic sheeting is normally recommended, ask your local agent/builder for advice. It is relatively inexpensive, and makes a huge difference.
The answer is, it depends. It depends on how far out of level it is. Some traditional builders build a garage with a slope to the front, because they know that water will blow under the up and over door. Please ensure that your base is level, you can always specify a timber weather bar to help prevent water, leaves etc. blowing under the up and over door.
I’m afraid that you will have to remove the ground at least 150mm (6”) away from the edge of the base, retain the rest of the ground and ideally dig out and fill back with gravel or pea shingle. You need to prevent water sitting on the edge of the base, and water draining on to the base from the surrounding ground. The concrete base should be cast at least 25mm (1”) out of the ground.
Square means that each corner is a 90degree right angle. The concrete garage has 90 degree corners, so if your base doesn’t, the garage won’t fit. To check that your base is square, measure the diagonal measurement (corner to corner). As long as both dimensions are the same, your garage base is square. If they are different, adjust your shuttering until both dimensions are the same.
Absolutely no problem. Simply mark on the base with a permanent marker where you want your building placed, remembering the advice above regarding positioning. A sketch of the base and the position you want may also help.
Refer to the leaflet The Concrete Garage Base. Your base should be designed for the ground conditions on your site. A reinforced concrete raft is essential, thickened edges and a compacted clean hardcore base, with dpm and steel mesh reinforcement as required. Advice from either our agent or your local builder is recommended.
Positioning your base is critical, but observing some simple rules will make sure that you will have no problems. Your up and over door will open through an arc which will need a maximum 1220mm (4ft). A standard height 1981mm (6’6”) up and over door needs 910mm (3ft) minimum space to operate.

Make sure the door will not foul walls, adjacent buildings etc. Allow for the personnel door opening. If the ground level is higher than the base (not recommended), the personnel door will not open.

If you need steps from the garage personnel door off the base, make sure you tell the agent/company so you will be able to position them correctly on the module of our panel sizes. LOOK UP! Overhanging branches of neighbouring trees – overhanging gutters from neighbouring buildings – the garage may fit on the base, but not at the eaves height…

Two main things:

  • LOOK UP! It may fit on the base, but do take into account overhanging tree branches and gutters/roofsheets of neighbouring buildings.
  • Make sure you take into account the opening projection of your up and over door and your personnel door, and any gutters that you may order.

You will need to ensure that you don’t break the rules from the local Authority, Planning and Building Regulation Approvals in particular.

What more authorative guide is there than the government web site?? Visit the Planning Portal to find out what the requirements are in your area.
He will send your order in to us for processing. We will check the order to ensure that we can build what you’ve ordered, and that there are no obvious mistakes, and then we will acknowledge it to you, with a week commencing date and together with a confirmation of order sheet. Please check that we have interpreted your order correctly, and then send that back to us as our confirmation. We will include a help the driver form, which we will need to have returned so we can allocate the right size lorry to be able to get to your base.

We will collect your balance of payment from you two clear weeks before the beginning of the week commencing date that we allocate to your order. We will assume that your concrete base has been laid well in time, and is pent square and level. If we are not able to deliver to the base or build on the programmed day, the building will be returned to Hanson and a minimum 20% redelivery charge will be levied. If there is space to deliver the building, we may leave the building on site, which will mean that you will not have to wait so long for us to come back and build your garage.

We will allocate a week commencing date based on the volume of work we have at any one time, on average our delivery periods are three to four weeks, providing we have collected the balance of payment two clear weeks before the programmed delivery. We will initially allocate a week commencing date and we will allocate a day of delivery towards the end of the week before that date, and advise you accordingly.
We deliver our garages on lorries that are large!
No, but we do ask you to mark clearly where you want the building to be positioned if the base is bigger than the recommended size, ie external dimensions +6” (150mm).
No, we will deliver the building components to your concrete base by means of a fork truck, or wheeled hand truck if there is insufficient access.
No, that is your responsibility, or your local agent may provide a service for you.
No answer found on website – please provide if keeping this question.
This will depend on the size of the building, but most buildings are built in under one day.
Where you tell us to, either in a diagram sent in prior to delivery or by you marking clearly the position required on the base – always speak to customer services before delivery to warn us that the base will be over size.
Please contact us and we will talk you through the procedure – it is simple, and won’t take long. If we cannot talk you through it, we will post you a set of instructions to work from.
Hanson Concrete Garages will take Cheques, Cash, or all of the main debit and credit cards (except American Express).