Waterproofing FAQ: What is the difference between water based and solvent based liquid waterproof coating products?
This article is part of a series about the waterproofing of buildings and constructions. It is relevant to residential and commercial buildings as well as civil engineering projects. It applies to both new build and for repairing an existing building. If you have a commercial project for which you require waterproofing products please contact us.
Having chosen a liquid membrane, as opposed to a sheet membrane, the next step is to decide whether to use a water based or solvent based liquid applied waterproofing membrane.
Both water based membranes, such as RBE : Rubber Bitumen Emulsion, and solvent based membranes can be used to waterproof roofs, walls, floors and foundations, however there are pros and cons which must be considered before choosing between them.
Advantages of Water-Based Waterproof Coatings
- No solvent fumes (no bad smell, no breathing hazard and no special need for ventilation);
- Water based is more environmentally friendly;
- During application, splashes can be cleaned off easily with water (no need for special cleaning agents);
- Equipment can be cleaned with water (no need for special solvent cleaner);
- Water-based coatings do not damage plastics or bitumen;
- Non toxic. Personal physical contact is not harmful;
- Water-based coatings can be applied to both dry and damp surfaces. This is a major advantage in situations where rain has fallen, or wet soil has been removed to expose a foundation that needs to be treated. In such circumstances the water-based coatings will take longer to dry, but the water in the surface will merge with the water in the coating and evaporate with it. In the case of a solvent-based coating, the surface must be dry in order for an application to be made.
Disadvantages of Water-Based Coatings
- It may be physically washed off if rain falls onto a freshly painted water-based coating;
- It is susceptible to frost damage when wet. Must be protected from frost during transport and storage.
Advantages of Solvent-Based Waterproof Coatings
- They produce almost immediate waterproofing protection after application, even before they have dried. Hence rain after application is not a big problem (however, rain before application is a much worse problem because they cannot be applied onto damp surfaces);
- They are not damaged by freezing temperatures (which is why they are so popular in Europe, especially during winter);
Disadvantages of Solvent-Based Coatings
- Some solvent-based products can be harmful to health;
- They give off solvent fumes and hence require good ventilation;
- Most are flammable;
- They can attack plastics and bitumen;
- Applicators will require special protective clothing and special hand cleaner to remove splashes;
- Special solvents are needed to clean equipment after use;
- Solvent-based products cannot be applied onto damp surfaces. They are incompatible with such surfaces, which must be allowed to dry fully (including all trapped moisture must be given time to rise and evaporate) before application commences.
Please note that any information or advice on this page is supplied in good faith and that while we make every effort to ensure that it is accurate, helpful and up to date, it is given without commitment or guarantee. We always recommend that trials are carried out prior to undertaking any work or contracts.
Please remember that orders have to be above our minimum size quantity.