Here in the UK, having a basement isn’t as common as in other countries but there are still a lot of houses that have them. For some, the basement is a bit like a garage – a semi-useful storage area that always seems a bit dark and damp. But for others, it is a useful space with potential that can be used for anything, from a TV room, playroom for the children, a home office or even a guest bedroom. The keys to achieving this usefulness is waterproofing the basement – but can you do it yourself?
If the basement hasn’t been treated in some time (or at all) then it is important to start with a few basic considerations before you think about doing any work. Depending on the condition of the basement, you may need some professional help, especially if there are signs of dampness.
Some of the main considerations are:
- Is there a damp or musty smell in the basement all of the time?
- Can you see any signs of dampness like crumbling plaster, black mould or tide marks on the walls?
- Have there been any changes to the water table since the house was built?
Causes of a wet basement
If you run into any of these problems, you could have what is called a wet basement. This means that the moisture levels in the basement are too high and causing damp walls and floors and other problems. Eradicating the damp needs to be a priority before you can start converting the basement to a useable living space, so you will need a damp proofing expert to look at it for you and advise you on the best method for making it dry.
High groundwater tables can be a major problem, especially if they have altered since the house was built. This will mean there is underground water against the walls of the basement that is being forced through under hydrostatic pressure. This will cause the bricks and masonry to absorb a considerable amount of water, which it time can undermine the strength of the walls and cause structural damage.
Once you understand what the problems are, you can start looking at waterproofing the basement and what steps you need to take to prevent these problems in the future.
Evaluate the perimeter of the house
The first thing to do is to inspect the property externally to determine how high the ground level is compared with the internal floor level. The walls below ground will be much damper than the walls above and will need the most complex damp proofing to prevent lateral damp penetration. If the external ground level slopes towards the property, some drainage may be required to discharge water away from the property.
It is always important to keep a property well maintained so making sure guttering is sound and clear and downspouts are aimed at the drains. This will enable rain to discharge straight into the drainage system and not into the property.. Also clear any large shrubs or trees away from the close proximity of the walls, because their roots can damage foundations and cause major structural damage.
Choosing the right waterproofing
This is an area you might want to chat with a damp proofing expert about – getting the right waterproofing system installed for your project is the most important thing. You can buy many types of waterproofing materials but choose the wrong one will mean money down the drain. You are advised to never start without expert advice from the BWA (Basement Waterproofing Association)
Prepare the walls
Cracks and weak spots in the walls should be repaired and made watertight before any waterproofing system is installed as these will make unnecessary weaknesses where water can enter. Again there are different products to use from sealants to epoxy that can penetrate right into the cracks. Your damp proof expert will also be able to recommend this kind of product.
Considering a sump and pump
Depending on how wet the basement is and what system of damp proofing is used, you may need a sump and pump. This is basically a hole in the basement floor that houses a special pump. It will have to include drainage channels and plumbing to discharge and incoming water into an external drain. When the water level in the sump reaches a certain level, the pump automatically switches on and pumps the water out. Installing this equipment is quite complex as it involves things such as excavating a section of the floor, installing a special chamber and fitting the pump. If your property has a history of flooding, installing a sump and pump is crucial.
Finish the waterproofing
Once the preparation work is done, you can apply the product that you decided in step 2 to the prepared walls. There are two ways of damp proofing basements one is to install a Cavity Drain Membrane system and the other is Structural Waterproofing (Tanking). There is a vast difference between the two because whereas Tanking blocks the damp from entering a CDM system allows it to enter, to be controlled to be discharged. Once the damp proofing has been completed, you can then look to complete and decorate your new room.
As with any project, there are things that can go wrong that you should be fully aware of. Always take the advice of experts when needed. Some examples of potential problems of DIY basement waterproofing can be:
- Your work might not conform to BS 8102 which is the standard that outlines the basement waterproofing and how it should be done – it isn’t a legal standard but it is the best practice
- You don’t install the system right and it leaks. Sometimes this can be disastrous because the whole thing may need to be done again.
- You don’t install the sump, pump or drainage system correctly which can flood your new room.
- You accidentally puncture the damp proofing system causing leaks.
Another problem you may incur in your new basement is condensation. Warm, moist air from the rest of the house hits colder air and walls in the basement and moisture is released onto walls or furniture. Always consider introducing ventilation into your new basement by installing Passive Vapour Vents (PVV)
You can waterproof your basement yourself but for the best results, you should work with a basement damp proofing expert such as Tapco HomeDry. That way you can get guidance on products and systems, help with the complex aspects of the work and ensure that it is done to the British Standards. The end result will be a basement that can be used for a wide range of purposes and will remain waterproof for many years to come.