Base laying for your concrete garage
Building a solid concrete base is fundamental to ensuring that every sectional building Dencroft manufacture and install stands the test of time.
Without a suitable base, your garage will lack stability and deteriorate rapidly. A well constructed concrete base will prolong the life of the building and eliminate the risk of doors and windows becoming faulty as a result of movement.
Our complete Base Laying Service includes:
- FREE SITE SURVEY
- Site Measurement & Design
- Dismantling & Removal of old Garage
- Removal & Disposal of Asbestos Material
- Excavation & Removal of old Base
- Groundwork & Preparation
- Concrete Base Laying
- New Garage Supply & Installation
Your concrete garage base
1. Think about where you want your new garage and consider the following: The base should be if possible higher that the surrounding area by at least 25mm (1″). If not any standing water could leak under the panels. If the area around the base slopes down to the base try and dig a 150mm (6″) trench around the base and fill with gravel to provide a soakaway. If your drive slopes down to the garage put in a gulley to take the water away.
2. Finally don’t forget to allow for the up and over door which can project upto 1220mm (4″) when opened. Also look up for any overhanging trees and buildings. Allow for the overhang of the roof and guttering, allow 150mm (6″) each side on an apex roof or 150mm (6″) to the rear on a pent roof.
1. Preparing the ground and getting it as flat as possible beforehand makes setting up the shuttering a whole lot easier and ensures a uniform thickness of concrete throughout the base.
2. Judge whether hardcore is required by assessing the firmness of the ground. If in doubt, use it, as the base is also the foundation of your concrete garage, but consider the finished height of the base too.
3. For soft ground issues, use steel mesh to re-enforce the concrete, or consult your concrete supplier about ‘fibre-crete’.
4. Never lay concrete over turf as turf will rot down over time and the base will become unstable.
5. If your site is prone to damp, use a damp proof membrane (thick plastic sheeting), but make sure to add the membrane to the whole base or a crack will appear where the sheeting ends as the concrete will dry at different rates.
6. If you are concreting up against a wall, use damp proof sheeting between the concrete and the wall, otherwise damp may transfer from the base into the wall.
7. Set up your shuttering at least a day or two prior to the concrete ‘pour’. There’s nothing worse than the concrete truck turning up earlier than expected and your site is not ready.
8. Make sure your shuttering is set up solid. You should be able to walk on it without it moving. Concrete is very heavy and will push the shuttering out of place if it is not securely pinned with timber stakes and nailed (or screwed) together.
9. Use a decent ‘weight’ of shuttering material. Something like a 100mm x 50mm or 150mm x 50mm timber is ideal, and make sure it is straight, not bowed. Obviously the height of the timber is going to denote your chosen thickness of concrete as you’re going to concrete up to the top of the shuttering.
10. The shuttering should be set up totally flat, level, square, and oversized. Do not set a ‘fall’ in the base for a concrete garage otherwise the whole building will lean with the base. Ensure that the shuttering is square by measuring from corner to corner diagonally, and make the internal shuttering dimensions around 150mm longer and wider than the proposed concrete garage size to allow for any brackets (6″).
11. Make a ‘door’ in the shuttering. It’s always a good idea to have a piece of the shuttering that can be lifted out of its pegs so access with your wheel barrow can be made into the base area and the concrete can be poured exactly where it is needed.
The Concrete Pour
12. Ensure your site is fully prepared before ordering your concrete. All shuttering set up, access clear, and tools ready.
13. You will probably need a rake, tamp, shovel, float, spirit level, gloves, Wellington boots, hose pipe, and wheel barrow, at your disposal.
14. Choose your preferred concrete supplier. Do not try to mix the concrete yourself on anything above 1 cubic metre. The ‘barrow-mix’ type companies are very handy because they will deliver on-site the exact quantity of concrete required so you can not under or over order. Plus they also ‘barrow’ the concrete into the base whilst you sit back and relax, leaving you with nothing more than the finishing of the concrete surface.
15. Be prepared for concrete spillage between the concrete truck and your base. A hose pipe is the best way of cleaning spillage, but it must be done before the concrete dries.
16. Ask the concrete company for a reasonably ‘wet’ mix, which will make finishing of the concrete easier especially in hot weather.
17. Get the concrete poured ‘in-situ’ in the base area, not in one big pile in a corner. When the last few barrows of concrete are required, put the shutter ‘door’ back in place and pour over the top of the shuttering.
18. Use your rake to get the concrete as level as possible with the top of the shuttering whilst it’s being poured. Remember it’s much easier to rake concrete than it is to shovel it.
19. Use a ‘straight edged’ tamp (make sure it’s not bowed), ideally just wider than the base width to drag back excess concrete and ‘tamp’ the levelled surface in order to smooth it, working off the top of the shuttering. Either do this from each side if you have help or from within the base (stood in the unlevelled part of the concrete) if you are on your own. Work from one end to the other.
20. Use a ‘float’ to smooth the outer edge of the concrete base, (the width of the float approximately 250mm) for a professional look. If you require a fully floated base then it is best to use a professional wide concrete float on a pole available from most hire shops.
21. If a ramp is required at the front of the base, either concrete this with the shutter in-situ and leave it in place or remove it after the concrete has set (if it will come out), or alternatively concrete the ramp on a separate day when the base has set and shutters have been removed.
22. Best to leave your shuttering in place for at least a couple of days, and ideally allow the concrete to cure for a minimum of 7 days before installation of your building.
23. don’t wash spilt concrete down drains as it will settle and block your drain over time.
24. It is always better to lay concrete with a friend, rather than trying to do it on your own.
25. Don’t be too concerned about rain on the concrete – it will still set but you may have to ’seal’ the concrete with PVA later as the surface can become ‘dusty’.
26. Cover the finished base with plastic sheeting if the rain becomes heavy
Finally if you need any help or advice please contact our head office where a team of experts will be happy to help.
ALL DENCROFT PRODUCTS ARE DESIGNED, PRODUCED AND INSTALLED TO THE HIGHEST QUALITY AND SPECIFICATION TO SUIT YOUR SPECIFIC REQUIREMENTS.
Contact us now on 0800 1182547 for a no obligation quote.
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