Blackfriar Interior Seal Damp
  • Blackfriar Interior Seal Damp
  • Blackfriar Interior Seal Damp

Blackfriar Interior Seal Damp


Blackfriar Interior Seal Damp is a clear coating which prevents damp patches from spoiling interior decoration. Formulated for use on surfaces such as plaster, brickwork, cement and mortar. Penetrates and seals surfaces against damp.

Product Details

  • Good penetration
  • Blocks and seals damp
  • Ideal for pre-decoration
  • Use on plaster, brick and cement
  • Interior use

**Available for delivery - see Delivery Options below**

VAT excluded

£19.37 Tax incl.


Blackfriar Interior Seal Damp is a clear coating which prevents damp patches from spoiling interior decoration. Formulated for use on surfaces such as plaster, brickwork, cement and mortar. Penetrates and seals surfaces against damp.


Ensure surface to be coated is clean, dry, sound and free from wax, grease or any other contamination. Mould growth should be treated with Blackfriar Anti-Mould Solution and allowed to dry.


Stir thoroughly prior to use with a broad stirrer. The product may be applied by brush, roller or spray. Apply at least two coats, lightly rubbing down between coats to prepare the surface for subsequent redecoration. Be sure to apply the product 300mm beyond all sides of the dampness.


Not recommended.


Do not use under cold (less than 5°C) conditions. This product will not cure the source of penetrating damp - the cause of persistent damp should be cured before applying Interior Seal Damp. Not for use over wallpaper. Will not cure efflorescence. Do not apply to wet surfaces. Application onto damp surfaces will prevent full penetration into the surface and prolong the drying time of the product.

Drying Time

Touch dry in 2 - 4 hours. Recoat after 16 hours and within 3 days. Drying times are based on an ambient temperature of 20°C and 50% relative humidity. Lower temperatures or higher humidity will prolong the drying and overcoating times.

Clean Up

Remove as much product as possible from application equipment before washing with white spirit. Do not empty into drains or water courses. Some local authorities have special facilities for the disposal of waste coatings.


Store in a dry, safe place. Do not store in environments where extreme temperatures may occur. Keep within 5 30°C. Do not store in direct sunlight.


  • Protect interiors from damp
  • Use on plaster, brick & cement
  • Ideal for pre-decoration

Please contact Rawlins Paints' Technical Support Team on 0113 2455450 for more information.

Product Details

Data sheet

Blackfriar Professional
Interior / Exterior Use
Water / Solvent Based
For Use On
Plaster, Brick, Cement
Application Method
Brush, Roller
Single, Two or Three Pack
Pack Size
1L, 2.5L
Base Type
Solvent Based
Interior/Exterior Use
Brush, Roller
Dry to Recoat (at 20°C)
16 hours
12m² per litre
Recommended Thinner/Cleaner
Do Not Thin/Cleaning White Spirit
Touch Dry
2-4 Hours
UN Number

Customer agrees that before placing an Order, Customer has read and understood the most up to date Product Data Sheet for the Product. Where we have access to the Product Data Sheet from the manufacturer, we will either provide a copy on request, or include a link to the Product Data Sheet available on the manufacturer’s website. Customer further agrees that we have no liability for any errors or omissions contained within the Product Data Sheets. For more information, please see our Terms & Conditions of Sale.

questions Margot Hummel on 2019-10-15 10:27:28

Water is penetrating my brick wall from the outside to the inside. I am unable to apply any form of brick sealing the outside. Will Interior Sealant stop water seeping through the brickwork?


For exposed interior brickwork or blockwork you can apply Zinsser Watertite but this must be applied to bare substrates only. If the issue is not resolved on the outside of the brickwork though, no coating will last on the inside.

questions Brian brogan on 2019-02-28 10:24:09

Will your paint prevent black marks appearing Problem down to condensation


Blackfriar Interior Seal Damp would not prevent mould. The best product would be Zinsser Perma-White Interior to resist mould however excessive condensation will form on the surface and can leave slight marks, (clear marks not black). Another good option would be Zinsser AllCoat Exterior (Water Based) Satin or Matt - these are less likely to leave any marks. Treat the mould first then apply 2 coats of one of the above products, surfaces must be completely dry before applying any paint coating.

questions Stephen  on 2019-02-15 07:40:54

Hi, Can this be used as a top layer on an already painted wall?


Blackfriar Interior Seal Damp should be applied to bare plaster. If applied to a painted wall which is damp the paint may blister up behind the Seal Damp. It will be best to sand off the paint in the damp areas before applying the Seal Damp.

questions Gary foxcroft on 2018-11-13 17:52:55

Can this be used on an interior bathroom with real bricks & stone.the bricks are fine but the stone is flaking away Badly . will this product prevent that.


Blackfriar Interior Seal Damp will darken the colour of the stone, if this is OK then brush the stone well to remove as much dust as possible, thin the first coat of the Blackfriar Interior Seal Damp with white spirit to act as a sealer coat, followed by 2 further coats.

If a clear non-darkening product would be preferred then the Blackfriar Quick Drying Varnish would probably be OK depending just how friable the stone surface is, brush off the loose material as above. Thin the first coat of the varnish with water then 2 full coats.

questions Lesley Callaghan on 2017-07-29 15:14:44
Question: Can the black friars paint be used on already damp walls that have penetrated ordinary emulsion on new plaster.

Blackfriar do say to apply the Interior Seal Damp to bare plaster however you can lightly sand the paint finish with the damp marks showing then apply the sealer. 2 coats can be applied then overcoated with your emulsion paint.

This product will only hold back minor damp problems, if there is a constant damp issue this should be resolved.


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