Designing a waterproofing scheme is no simple matter. With rainfall averages varying from a few hundred millimetres to several metres depending on where you are in the UK, and most of it undulating, it’s certainly no level playing field. Even when it is, you could still find your building sitting
No one wants to come home to find water damage to their basement. There are easy steps to take which can lower your risk and prevent this experience in your home. Companies like Helitech outline the basic ways to keep your basement safe from water damage. If you use professionals
Added Green Roof protection for former WWII bunker with Blackdown Green Roof and Derbigum Waterproofing Originally built in 1941 as a special decoy target for German bombers, The Decoy Bunker is tucked away in the rolling hillsides of Monmouthshire and has been fully restored as a unique holiday home. As
BDC 319 : Aug 2024
Designing a waterproofing scheme is no simple matter. With rainfall averages varying from a few hundred millimetres to several metres depending on where you are in the UK, and most of it undulating, it’s certainly no level playing field. Even when it is, you could still find your building sitting below the water line. Here, Niklas Ullfors, National Technical Manager for Visqueen, lays down some ground rules for specifying successful waterproofing solutions. With the UK’s weather becoming more and more unpredictable, and taking in to account the local geology, it is imperative to have a varied range of robust waterproofing applications to meet any requirement. While average annual rainfall across the country is 1.35 metres, some parts of Scotland and the East of England suffer a drenching of 3.0 metres and over. In most cases this filtrates through the soil types until it reaches the natural water table and is far enough below the surface not to be troublesome. However, in places such as the fenlands in East Anglia the water table is at or just below ground level and as a result, without an appropriate waterproofing scheme, a building could be sitting in water 100% of the time. Terrain can also play a big part when selecting the appropriate waterproofing system. Few parts of the UK are flat and there isn’t a real option to have land remodelled, because it is expensive and a significant engineering exercise. An alternative is to follow the natural gradient, with the front of the building at ground level and the rear partly below it, or vice versa. Some buildings are deliberately ‘buried’ to blend into the landscape and be energy efficient, while others feature a single or multi-storey basement. In all these cases, a robust waterproofing system will be needed. Obviously, it’s essential the waterproofing design is done at the building design stage and dovetails into the overall design. The British Standard code of practice for the theoretical design of waterproofing systems for a building or civil engineering structure is BS8102:2009. Introduced in 1990 it was updated in 2009. Whilst it is recognised as a guidance only document, a number of recent legal cases have created a default system whereby it must be considered when designing any waterproofing scheme. Know your ABC’s Waterproofing systems are split into Types A, B and C, and range from pre-applied and post-applied solutions, through to integral and drained systems. Depending on the amount of water encountered one or more types could be required. The most common are single and dual type applications. A waterproofing design with a combination of types lowers the risk for water ingress. Type A A ‘Type A’ system is bonded to the external face of the building or structure. It is completely bonded and known as a ‘Type A fully-bonded’ system. When a fully-bonded system needs to go below a building then the product will be placed on the ground first and the concrete poured on top of it. This is known as a ‘pre-applied product’, whereas if for example, a liquid product is applied to the external face of a structure this is a ‘post-applied product’. Both are Type A systems as both are fully-bonded to the structure. In the unlikely event the Type A system is damaged then water can enter through the damaged area. But tests have proved the water will stay localised to the damaged area. Conversely, if the system is not bonded to the structure then the water will track between the Type A product and the structure, and as a result water ingress will occur on a massive scale! Type B A Type B integral system is generally used when walls that are made from cast-on-site concrete and need to be made waterproof. There are two ways to achieve this. Firstly, you can add a special additive, which is done at the concrete mixing plant. This is very common as it is the most efficient way to make concrete waterproof and is also the most cost effective. Secondly, steel reinforcement can be added to the structure. This will keep the concrete taught and prevent any tiny crack appearing. If cracks do appear, then water will travel along them and enter the building. Type C A Type C system is completely different and often referred to as a ‘drained cavity system’ as it allows water to enter into the building through the structure itself. The water is then collected and managed away via a specialist drainage system. This system is very common if, for example, a building is being refurbished and water ingress has occurred or the building is undergoing a change of use. Design considerations Having considered external factors, a waterproofing designer also needs to consider the use of the proposed structure, what materials are going to be used and that the solution will remain intact for the in-service life of the building. The environment and building use creates risk factors, which are categorised under BS8102:2009 into three grades. Grade 1 has the lowest risk, a car park being a good example. Grade 2 would include a garage, plant room or workshop, whereas a domestic dwelling is a Grade 3 environment, needing to be the driest. Any water ingress or damp patches on the walls in your home are totally unacceptable. Once all the background information and the risks are known, then we can start to consider the principles of the waterproofing design. To provide a working example I’m suggesting a domestic house with a basement in Cumbria in the North West of England. The building is at risk from high levels of rainfall and, as it is a grade 3 property, it needs to be dry at all times. At this initial stage we will be considering a dual waterproofing system. In this situation, a Type A + Type B system would be highly recommended and is a fairly common combination for a new build. The Type B system will be an additive added to
No one wants to come home to find water damage to their basement. There are easy steps to take which can lower your risk and prevent this experience in your home. Companies like Helitech outline the basic ways to keep your basement safe from water damage. If you use professionals to install these basic safeguards, your basement will likely remain livable and water-free. Ways to Prevent Water Damage Basement Waterproofing Crawlspace Waterproofing Exterior Waterproofing It is important to address not just one, but all three of these components of a waterproof foundation. Once you begin to have a problem with water damage, it tends to quickly become worse. Waterproofing a basement or foundation can be a lot of work. It requires skill, and it is necessary that it be done correctly. This is an area in which you might want to consider hiring professionals rather than doing the project yourself. It’s not an easy job so leaving it to foundation repair Canyon Lake would be your best option. There are several sites online which will provide you with DIY procedures if you want to take on this task. However, by using a company like Helitech, you can ensure that you are having the best-patented components on the market installed to protect your foundation. You also will have the satisfaction of knowing that your project has been done right and that your basement is truly protected from water damage. Dangerous of Insufficient Waterproofing Of course, sitting water and constant dampness cause structural damage over time, but there are also other dangers that come along with not having your foundation effectively waterproofed. High humidity can foster the growth of mold and other undesirable bacteria, and this can attract bugs and various pests into the basement and home. Proper sealing can keep you from having to deal with these pests. Water that sits too long can become a breeding ground for mosquitoes within your home. These more aggressive pests can also spread diseases to your family and make life uncomfortable within your home. Any type of larvae growing within puddles in your basement can become a risk for your family. If you have sitting water, it is advisable to go ahead and mop it up and dry out the area with a fan. We will explore some of these best practices for maintaining a waterproof foundation in the paragraphs below. They are easy steps, which can save you a lot of money and protect both your family and your home in the long-run. You want to make sure your family is safe from risks that could cause them to be sick. Mold is often associated with sickness and household pests can carry diseases that can be communicated to your family members. These pests won’t stay in your basement for long either. If you begin to have a problem in your basement, chances are it will spread throughout the rest of your house. Basement Waterproofing The basement moisture barrier is the first line of defense in protecting a home’s basement from water damage. This barrier is made of panels and connectors which match. It can give your basement a more refined look and homey feel, while also protecting it from water damage. This structure removes water 70% faster than other drainage systems, and it is more aesthetic to look at. These panels will go right along with the walls and décor you may already have in place in your basement. While they are serving the purpose of quickly ridding the area of water in the case of flooding, they are also adding value and beauty to your home. You do not have to use a gaudy contraption to keep your basement safe and dry. Crawlspace Waterproofing For Crawlspace protection, a moisture barrier should be laid down underneath each of your home’s crawlspaces. This barrier keeps small amounts of moisture from entering your structural wood and causing slow damage, which can become detrimental over time. There are several problems that can be associated with damp crawlspaces, and you want to ensure your home is protected from these. Naturally, after rains, water seeps through the ground and the area under your crawlspace can become wet. Humidity will force this dampness up into your floorboards and your basement. This creates problems that often spread quickly. Once one area is affected, typically the rot and damage will spread to other areas of your basement and home. First, the slow rot of the wood can spread and compromise the structure of your home. Secondly, dampness promotes the growth of mold and harmful bacteria and provides a breeding ground for traditional household pests. Taking small and easy steps, like having the moisture barrier installed, can keep you from having to deal with these problems under and within your home. Professionals will lay down the moisture barrier between the ground and the structure of your crawlspaces to keep dampness from spreading and infiltrating the structure of your home. This is a simple, yet effective practice that can save you a lot of money, time, and frustration down the road. Along with the moisture barrier, sump pumps should be installed in your crawl spaces to help pump out excess water. This will minimize your drying time and keep you from having to repair water damage later down the road. Sump pumps are fairly small and inexpensive. Exterior Waterproofing Exterior basement waterproofing is just as important as protecting your basement from within. This seals the water out of your basement, and over time can prevent the costs of replacing boards and restoring your basement after water damage. This is essentially the first line of defense against water entering your basement and causing damage to your home. In exterior basement waterproofing, a sealant is applied to the outside structure of your basement, keeping water from reaching the inside of the basement in the first place. Professionals are able to apply this sealant to places that would not necessarily be easy to reach if you took
Added Green Roof protection for former WWII bunker with Blackdown Green Roof and Derbigum Waterproofing Originally built in 1941 as a special decoy target for German bombers, The Decoy Bunker is tucked away in the rolling hillsides of Monmouthshire and has been fully restored as a unique holiday home. As the bunker had to blend directly into the hillside, a highly durable waterproofing system was needed to provide full protection against water travelling down from the surrounding landscape: a green roof waterproofing solution that would provide the desired ‘camouflage’ effect by using the existing soil and grass from the surrounding landscape. Alumasc’s Registered Contractors Span Roofing installed Blackdown Greenroof Drainage Layers, Intensive Substrate and Washed Pebble Ballast to finish the green roof. A Derbigum Black Anti-Root Built-Up System sits below the green roof and provides a highly reliable waterproofing solution and maximum peace of mind for the future, as the Derbigum system holds 40-year durability certification with the BBA (British Board of Agrément). To find out more about Derbigum Waterproofing Membranes click here, for more Green Roof Information click here. Further details about Alumasc’s full range of waterproofing systems can be found at www.alumascroofing.co.uk or call the Alumasc technical team on 03335 771 500.
