How to Waterproof a Cellar

Most newbuild homes in the UK are not built with cellars, with a growing tendency being to build up rather down to reduce costs and provide more floorspace. In centuries past, some Victorian and Georgian houses were built with cellars to accommodate living space for servants, and in less wealthy households, to act as storage for coal and household fuel.

The reason we tend not to build cellars is because the UK has a wet climate which means there is a lot of sitting groundwater, leaving cellars and underground levels susceptible to damp. Here at Garratt's Damp and Timber, we often get called out to undertake cellar waterproofing in London, mainly in older properties.

Many people are curious about the basement waterproofing process, with some wondering if they can do it themselves. If you have a cellar or an underground level and are curious about waterproofing it and how to go about it, we’ve put together some handy tips and an overview of the process we use.

What Causes Damp in Cellars? 

Firstly, let’s look at what causes a damp cellar. There are a number of reasons why a cellar or a basement might be damp, with the most common reason being excess groundwater seeping through the walls and up through the floors. Most houses with cellars are old, meaning the materials and methods of construction used during the original build differ greatly from those used now. Factor in wear and tear over hundreds of years and it’s easy to see how damp might become a problem.

Other issues that can cause basement dampness include inadequate plumbing and/or guttering, but particularly wet weather can also have an impact.

Professional Basement Waterproofing

There are two main basement waterproofing systems that we use to keep cellars secure and free of damp. As a first port of call we use cementitious tanking, also known as Type A waterproofing. This is a good option for most basements and involves using renders, slurries, or epoxy resins on the internal walls/floors to create a waterproof seal that will prevent water from penetrating the internal side of the wall. It’s mostly used in areas where is no existing structural damage, and where there isn’t a high level of ground water.

For homes with structural fragility caused by damp or in areas where there is a high volume of sitting ground water, Type C waterproofing, also known as membrane tanking or a water management system, is the best course of action.

This involves installing a sump and pump system drainage channel around the perimeter of the property which will trap water close to the basement and direct it away into nearby drains. This prevents water from getting close to the basement altogether, whereas Type A tanking simply involves stopping water from penetrating interior walls. It does not stop water permeating the actual cellar structure.

Whether you have Type A or Type C basement tanking, it is advisable you get one or the other for a permanent solution to best protect your cellar.

 Cellar Waterproofing Cost 

Like most house projects, many people question what the cost of waterproofing a cellar is. There is no set cost because there are many different factors that can influence the overall price, including the size of the basement, the level of ground water, the type of system that is being used, and whether or not there is any damage (unforeseen or not) that needs addressing.

We recommend getting a site survey from our team. It’s completely and there is no obligation to use Garratt's Damp and Timber for any work that is carried out, although we do have over 20 years of experience in basement tanking and are experts in the field.

Our specialist team will come out to your property and assess what the source of damp is and give you a recommendation for treatment moving forward. We can also provide further advice about waterproofing your home. We will then give you a quote.

Cellar Waterproofing in London

We work across the London and Greater London area. If you’re local to us and want to find out more about basement tanking and waterproofing your cellar, please call us on 020 8535 7536. Alternatively, contact us online to enquire about a site survey.