A guide to using Bitumen for Damp Proofing

A guide to using Bitumen for Damp Proofing

A guide to using Bitumen for Damp Proofing

Bitumen (commonly referred to as asphalt) is typically thought of as a material for construction, usually with building roads. However what you may not realise is that this material can also be effective when it comes to damp proofing your home.

Importance of Bitumen for damp proofing

It can’t be emphasised enough, weather-proofing and damp proofing helps prevent damage to a property. Moisture ingress can potentially result in timbers rotting and long term structural damage.

Furthermore damp can result in condensation and black mould. That in turn can cause health problems, especially if you are suffering from allergies or are prone to chest infections.

Using Bitumen based primers and paints to damp proof has gone on for years and will do for years to come.

The absolute key is to understand what the damp problem is, why it has come about and what is the best way to solve it. In simple terms, if a wall is wet because of a radiator pipe leak then no need to be applying Bitumen paint on the wall. In other words, find the problem and fix it.

Bitumen paints only act as barriers. It does not mean the damp goes away and if not solved, the Bitumen simply de-bonds as shown here. There is no damp proof course in this wall meaning damp coming up from the ground is always a potential problem. The Bitumen paint simply broke down over time, allowing damp to come through and even the staircase stringer rotted.

Not the proper solution in this case.

All too often, we come across this as a builders solution. Often because it allows them to dot and dab plasterboard or plaster to it as soon as it has dried, collect their fee and move on. The damp returns not too long after and the property owner is back to where they started and because of the further damage, the work is even more expensive second time around.


How effective is Bitumen for damp proofing?

You may not know this, but Bitumen as a form of damp proofing is nothing new. Believe it or not, its waterproofing properties have been used for thousands of years and in fact, it is referenced in the Bible; as caulking for Noah’s Ark and Moses’ cradle.

Bitumen is actually a natural material which oozes from the ground in certain places of the world. Technology has evolved and advanced the principle of using the material as a means of waterproofing. Nowadays bitumen or bitumen derived paints and tapes are used in all manner of internal and external damp proofing and waterproofing applications very successfully.

Additional benefits of using Bitumen

Another additional benefit is that bitumen can be used as an adhesive for wood, insulation boards or as a bonding agent (specifically on plaster or for more difficult circumstances.)

Furthermore. it can also be used for tanking silage pits (specialised brushes are available for this).

Different Bitumen products

In the UK alone, there are hundreds. if not possibly thousands of different brands and types of Bitumen based damp proofing and waterproofing products.

It is our experience that quite often, given Bitumen based products are ‘commodity’ products, the cheapest brands are selected.

The questions to ask is why is one version of bitumen paint for instance is cheaper than the next? In almost every instance of a commodity product being cheap, (Builders Merchants Special Offers aside), will be down to level level of what we call in the industry; ‘Active Ingredients’. Active ingredients are the thing that makes a product work in the way it is intended to work.

Different uses for Bitumen

The other thing we find here at Alliance Remedial is a lack of understanding for selecting the right Bitumen product for the job it is intended for. For instance, Bitumen is used in the construction process of roads and roofs. Two very different applications in so much as each application would have different usage criteria. This would mean the type of Bitumen product would have to be relevant to that use. One for instance may well mean it is exposed to extremes in temperatures, sunlight, wind and rain and the other, sandwiched between other materials and protected against weathering.

Some Bitumen products are cold applied and simply brushed on and others are hot torch applied.

Some require that a Bitumen compatible primer is applied to a surface first before applying the main Bitumen product which will provide a better bond to the surface.

To summarise, Bitumen is an age old solution for damp proofing and waterproofing in many different ways. The success and durability of a Bitumen application always comes down to selecting the right type of Bitumen product for the job it is intended for. We also advise that you do not buy cheap. If it’s cheap it will be due to lower levels of active ingredient and the consequence is the product will not last or be as effective as the dearer brands.

You know what they say; buy cheap and do it twice when it comes to damp proofing your home.

We supply a number of Bitumen based Primers, Paints and Tapes all of which, we are satisfied are of a good quality and can be used to treat and prevent damp from occurring within your home.

If you would like to know more about the range of damp proofing and other products we have available you can contact us on 01329 235252 or via e-mail info@allianceremedialsupplies.co.uk and we will be happy to answer any questions and help find the right products to suit your needs.


4 thoughts on “A guide to using Bitumen for Damp Proofing

  1. admin_chris says:

    Hi Stephen, without any images to work from it is difficult for us to answer fully or with 100% accuracy. You might be referring to the original dpc material under the wall plate the floor joists are sitting on in which case a bitumen paint or latex polymer paint is a suitable alternative however, you must do a thorough job of removing the old and de-bonded asphalt before applying the new product.

  2. admin_chris says:

    Hi Prashant,

    This is a very good question!

    Firstly, the surface has to be well prepared to accept a liquid coating. Where a bitumen coating is already down it should be thoroughly brushed/scrubbed to remove any loose or blown bitumen. Some of it will still be bonded very well and that is fine. It should also be jet washed to be clean and free of dust and dirt.

    There are several types of liquid waterproofing paints. Bitumen, Acrylic, Latex Polymer, Polyurethane, liquid asphalt and so on. The first thing you should look for is the data sheet stating the product is UV stable. The ability to withstand the suns rays over time.

    For bitumen already being down, most products will bond to it but you will need to apply a good quality primer that is compatible with the top coat liquid you have decided on. The primer will act as the bond between the bitumen and the top coat liquid membrane.

    Where you have changes in direction and protrusions you are advised to apply a reinforcing textile tape between each coat of the top coat.

    The top coat to be applied in two coats.

    So, the key is all about thorough preparation, a good quality primer, the use of reinforcing tape and two good, high build-up coats of your liquid membrane. Any of the types I have listed above are suitable.

    Do not scrimp on cost. A bit like getting a bottle of own brand fairy liquid in a budget supermarket, you never get the same amount of bubbles as the real brand because it is a watered down version!

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