This project has been written with the help of Property Repair Systems, who are experts in treating damp, particularly regarding all types of garage floor and wall repair and coating. If you need any help with garage floors or walls, including dampness problems Property Repair Systems expert staff will give you completely free, no obligation advice on 01626 336180. The information you need may be in the project below. If not, we recommend that you call them. Garage floors were not typically laid by the builder of your property to the same standards and guidelines as floors that are going to form part of the living space. As they are not going to be part of your inhabited area there is no need to go to the time and expense of ensuring that they are damp proofed to the same standards as internal floors would be. Similarly, the walls were not usually constructed to cater for a living space and therefore if you convert your garage into a living space, bear in mind you may have to deal with these short-comings.
These two possibilities mean that you may have to deal with three problems if you want to use your garage as a living or truly dry storage area; You need to know what you are dealing with before you start any conversion of your garage into dry storage or even a habitable living space. So, to be able to cover the floor with any type of flooring you need to: Checking your Garage Floor for Damp: clear and brush an area of the garage floor so that it is totally free from any loose materials. Now cut a small square of plastic around 100mm x 100mm and, using plastic tape, tape it to the floor area on all four sides and leave it overnight. If there is moisture evident in the morning then this will confirm that the floor is damp. If the result sof the above test confirm the presence of damp then before you can lay any type of flooring you will need to seal the surface and also any floor to wall joints. Currently, moisture is evaporating into the existing, well ventilated, uninhabited garage and this will generally cause no issues because it is removed through ventilation in the space.
However, when you turn it into a living space, the room will be insulated and the ventilation will be much reduced so you can heat it effectively. If you do not seal the surface of the floor, this moisture will be the cause of some serious issues when it condenses on cold surfaces causing mould to grow and due to this can also cause rot in timbers. If you decide to lay a wood floor it will absorb this moisture, swell, lift and eventually also rot. It is essential that the concrete floor is sealed and made damp proof. There are two main approaches to doing this: Use a Vapour Barrier Membrane or Damp Proof Membrane When damp proofing a concrete garage floor, a plastic dimpled membrane is required if the floor is going to be boarded (either with chipboard, plywood or similar) or if a concrete screed is going to be laid. Floor Membrane from Property Repair Systems - roll out and lay on either chipboard, plywood, MDF or screed You might consider a slimline membrane which is ideal if you intend on laying carpet over your floor.
Slimline floor membrane used when laying carpet This can be painted directly on to the surface of the floor after a little preparation. This will seal the concrete floor creating a moisture barrier preventing damp entering the garage. We suggest that you use a liquid product, such as Ultra Epoxy Seal supplied by Property Repair Systems. Epoxy Seal Coat – coat the floor to seal – also available in different colours For your damp proofing to be effective the damp floor will need to be prepared correctly regardless of the product or technique that you choose to seal it with. There is a joint between the floor and the wall where the two meet. This is often quite rough and open to the elements and provides the point where much of the moisture can enter your garage. This joint needs to be opened up, cleaned and then filled with a waterproof material. This will then seal the joint between the wall and floor eliminating and potential future problems. A good solution to fill this joint is a Structural Epoxy Pouring Grout.
The joint will need to be opened up to approximately 25mm x 25mm (1 inch x 1 inch) for this to be effective. Opening this joint can be done with a disc cutter (angle grinder) and a stone blade. You should wear safety goggles and a face mask for this job as it is very dusty indeed. Keep the garage door open while you are doing this. Having cut down 25mm or so into the floor, you will need a lump hammer and a 25mm cold chisel to bash out the concrete. Smooth the bottom of the small "trench" with the chisel so there is as little variation in the depth along the length as possible. Alternatively you can cut this joint out with a hammer and bolster chisel which is much harder work! Once the joint has been sealed, the floor can be coated. Whichever coating you choose, it must be laid up the wall far enough to join with the existing DPC. If you are using the Vapour Barrier Membrane, then this should be rolled out over the floor and turned up at the edged where the floor meets the walls.
This should create a ‘tray’. It is important that the up-turned edge of the membrane is high enough to rise above the chosen flooring. This will then protect the ends of the flooring from getting damp. The over lapping joints, where the rolls of membrane meet and the corners, should be sealed with double sided tape. The skirting will hide the turned up edges of the membrane, or the up-stands, as they are commonly referred to. The advantages of this system are. Alternatively, apply a liquid epoxy membrane to a clean, dry concrete floor. This can be applied with a brush or a roller and the amount required will depend on the absorption of the concrete and the roughness of the floor surface. Typically this will be between 2.5 and 7 Sq m per litre. There are advantages with this system, although it is typically a little more expensive. There are a number of floor coverings that you can lay over a sealed garage floor. The choice of floor will have some impact of the method that you should use to seal the concrete floor.