Waterproofing – How to Guide

We know from experience that when it rains in Malta and Gozo, it really rains!!

When the water starts seeping its way in through inadequately waterproofed ceilings and walls, it is time to address the problem.

This is R.A & Sons guide on Waterproofing your property. Besides RALASTIC, we have four new products to be used effectively in waterproofing your home or building.

Planning & Preparation

It is essential to assess the substrate for humidity. This must be addressed first before commencing any work. If you are unsure of the humidity level then please ask for assistance from R.A & Sons.

  • The area must be cleaned properly. It is to be free from dust and any other loose particles. Any superficial imperfections such as holes or cracks must be filled with any suitable putty or touch up mortar and then smoothed.
  • Make sure any previously painted surfaces are in good condition and in case of need, remove the decaying, non-adhering and high thickness parts, by sandblasting or brushing them out, as well as any mould or algae present.
  • It is advisable especially on outside walls to use RAPRIMER. This allows a surface to harden, increasing the resistance in the absorption of the masonry, so that when RALASTIC is applied it can form an effective waterproof layer.
  • Leave RAPRIMER a minimum of 12 hours and up to 24 hours to dry dependent on weather factors.


  • After RAPRIMER is dry, apply two coats of RALASTIC. These layers must be evenly applied to allow proper compactness and coverage preventing water seepage between the membrane and backing. Seal all the corners and bends between the walls and floor.
  • RALASTIC can be applied by means of a hard bristle brush or a wool paint roller.
  • Let 24 hours rest between the 2 layers.


It is highly recommended to not use less than 1 Kilo per Sq Metre.

If the substrate is a roof, then it is also highly recommended to use RANANOSEALER to give extra protection (please consult

Providing these products have been correctly applied and subject to outside weather conditions, this should last approximately 5 years.

New Products

These are bitumen based products:

  • RALASTIGUM ST – this can be used with Elasticoating and with white felt to build up layers ensuring effective waterproofing. These can also be purchased from R.A & Sons
  • RALASTIGUM FR – this product contains fibres
  • RALASTIGUM ST ANIROOT – containing a repellent against tree and plant roots making it an ideal product to use outside before laying tiles.

If you have a waterproofing project that you need any assistance with then please ask the team at R.A & Sons who will be happy to help you in any way


Whilst every effort has been taken to confirm the accuracy of the information presented in this article, R.A. & Sons Ltd and R.A. & Sons Manufacturing Ltd cannot be held responsible for errors and / or omissions or for any direct or indirect consequences resulting from the use and application of its products.

The company expressly disclaims any and all liability as to any results obtained or arising from any use of its products or reliance on such information; no warranty of fitness for any particular purpose or any other warranty, expressed or implied, is made concerning the goods described or the information provided herein.

If you have any questions please contact us here.

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