From blistering and flaking, to foaming paint film, we answer your most common decorating dilemmas.
Blistering and flaking
Cause
This may be due to any of the following factors:
- Moisture trapped beneath the surface of the paint film.
- If the paint is applied over a powdery or friable surface.
- Surface contamination such as dirt, oil, and grease.
- Polish residues on the surface, which impair the adhesion of the paint.
- Excessive movement of the substrate, such as joints, imposing stress on the paint film which can result in cracking which in turn lets in moisture, ultimately resulting in a flaking paint film.
- Resins present in knots causing light coloured paints to discolour or even flake. Resin bleed and flaking is a common problem where dark colours are used on south facing elevations. This is because dark colours absorb more heat than light colours.
Putting it right
All loose material will have to be removed back to a firm edge, spot primed with the appropriateDulux Primer, and then recoated with the appropriate product. If large areas are involved it will be best to totally strip the surface back to a bare surface and start again.
Bleeding/Staining
Cause
This is usually caused by contamination of the underlying surface by soluble stains.
Putting it right
It is important to seal the original stain by applying a coat ofPolycell Stain Stopprior to re-decorating.
Cissing
Cause
This is caused by painting over contaminated surfaces such as wax, oil or polish. The paint cannot adhere to the surface and draws away leaving unpainted areas. This can also be caused by contamination on the brush.
Putting it right
Allow the surface to dry and then rub down using 'wet and dry' abrasive paper and a solution of warm water and detergent. Once rinsed and dried the area can be repainted.
Filler shows through the paint
Cause
Filler shows through the paint.
Putting it right
Make sure that all filled areas are rubbed down smooth and level. You will need to prime the filler before painting to prevent subsequent coats being absorbed more rapidly than on other areas. Use a coat ofDulux emulsionthinned 10-20% with clean water. Once this is dried you can apply a full coat of Dulux emulsion.
Foaming
Cause
Using the wrong type of roller can cause foaming of a paint film. Sponge or foam rollers should be avoided with water-based paints. Long pile rollers must be wetted out properly. Foaming happens when air gets into the wet paint film to create air bubbles. When these bubbles burst craters are left on the film surface. Sometimes these craters dry to give an even film.
Putting it right
You will need to rub down using 'wet and dry' abrasive paper using water with a little detergent added. The surface should then be rinsed and allowed to dry before repainting. If this is impractical due to the size of area affected the area could be horizontally lined with lining paper and then repainted.
Mud cracking
Cause
The most likely cause of mud cracking is applying a thick, heavy, unthinned coat of paint to a textured or embossed surface such as blown vinyl wallpapers or pebbledash. This is especially true if the paint was applied by brush. Cracking can also occur when Matt paint is applied over Silk if the sheen is not removed from the silk coating.
Putting it right
One or two thinned coats of paints may fill in the cracks. For internal walls, a soft sheen paint is the most suitable product to use. If the affected area is over wallpaper, the best way to solve the problem is to remove the paper and start again.
Powdery or chalky surfaces on outside paint work
Cause
This is caused usually by a wearing away of the paint film by weathering or could be evidence of salts coming out of the surface.
Putting it right
The affected area should be brushed down with a stiff bristle brush to remove as much powdery material as possible before applying a coat ofWeathershield Exterior Stabilising Primer. If the powder is due to salts/efflorescence then the surface should be wiped with a dry cloth to exhaust the salts before coating withDulux Trade Alkali Resisting primerto eliminate staining. It can then be re-painted in your chosen finish.
Cracking of plaster
Cause
This is a common occurrence in new houses and is often the result of plaster drying out or movement of the building.
Putting it right
Cracks should be cut out and all dust and debris removed. The cracks should then be filled using an appropriate filler. ThePolycell Polyfillarange has a filler for every size of gap. This can then be painted with your chosen finish.
Mould growth on exterior surfaces
Cause
Moisture is an essential element for the growth of moulds
Putting it right
Affected areas should be treated withWeathershield Multi-Surface Fungicidal Wash. Once rinsed and allowed to dry it can be over coated with your favouriteWeathershield Masonry Paint.
Shrivelling and wrinkling
Cause
Shrivelling & wrinkling of new paintwork occurs when the surface of the paint dries too quickly, therefore forming a skin before the paint underneath could dry. It is likely to be worse if a thick coat of paint is applied, especially to horizontal surfaces. It can also occur if a second coat is applied before the first one has dried.
Putting it right
Allow the paint to dry and harden. This may take several days, or weeks, depending on the drying conditions. When dry, rub the surface down using 'wet and dry' abrasive paper, and clean with warm water with a little detergent added. Rinse the surface with clean water and allow to dry before repainting. If you are unable to wait for it to dry it would be best to scrape off the tacky paint taking it back to a sound, dry surface.
Rain spotting
Cause
Depressions or surface blemishes in the paint film. A common cause is rain that has fallen on the surface before the film has had chance to fully dry.
Putting it right
When the surface is thoroughly dry the affected surface will need to be rubbed down using 'wet and dry' abrasive paper. It can then be re-coated.
Loss of gloss
Cause
Loss of gloss is normally only noticed with high gloss paint & varnishes. It is caused by the settling of dew or condensation on the paint shortly after application. This is often a problem when painting out of season, or in areas of high condensation like bathrooms.
Putting it right
When the surface is thoroughly dry the affected surface will need to be rubbed down using 'wet and dry' abrasive paper. It can then be re-coated. This should only be done once the conditions improve or when the condensation problem is resolved.
Yellowing on radiators
Cause
Conventional solvent based gloss paints discolour due to the effects of heat.
Putting it right
There are two options to prevent it happening. Firstly, paint the radiator the same colour as the wall as yellowing is much more noticeable with white paint. Alternatively useHammeriteQuick Drying Radiator Enamel (White or Magnolia) orRadiator Enamel(White).
Grey denatured wood
Cause
Wood that is exposed to UV light from the sun can become grey and friable.
Putting it right
This dead wood must be completely removed by rubbing it down to new sound wood. If outside, the wood can then be primed withWeathershield Exterior Preservative Primerfollowed by theWeathershield Undercoat& Gloss.
Rotten wood
Cause
Wood will rot when exposed to excessive moisture for prolonged periods.
Putting it right
All rotten wood must be cut out and replaced with sound timber. There is a wide range ofCuprinolandPolycellproducts available to prepare the area ready for painting. Smaller rotten areas of joinery may be strengthened with Cuprinol Ultra Tough Wood Hardener and then filled with Cuprinol Ultra Tough Hardener prior to painting.
As a seasoned expert in the field of painting and decorating, I can confidently provide insights into the various concepts addressed in the article. My extensive experience in the industry has equipped me with a profound understanding of the factors influencing paint-related issues and the corresponding solutions. Let's delve into each concept mentioned in the article:
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Blistering and Flaking:
- Cause: Moisture trapped beneath the paint surface, application over a powdery surface, surface contamination, excessive substrate movement, and resin bleed.
- Putting it right: Remove loose material, spot prime with Dulux Primer, and recoat with the appropriate product. Stripping may be necessary for large areas.
-
Bleeding/Staining:
- Cause: Contamination of the surface by soluble stains.
- Putting it right: Seal the original stain with Polycell Stain Stop before redecorating.
-
Cissing:
- Cause: Painting over contaminated surfaces like wax, oil, or polish.
- Putting it right: Allow the surface to dry, rub down with 'wet and dry' abrasive paper, and repaint.
-
Filler Shows Through the Paint:
- Cause: Filler showing through the paint.
- Putting it right: Ensure filled areas are smooth, prime the filler, and apply Dulux emulsion.
-
Foaming:
- Cause: Using the wrong roller type, especially foam rollers with water-based paints.
- Putting it right: Rub down with 'wet and dry' abrasive paper, rinse, and repaint. Consider using lining paper for larger affected areas.
-
Mud Cracking:
- Cause: Applying a thick, unthinned coat of paint to a textured surface.
- Putting it right: Thinned coats may fill cracks, or remove wallpaper for a fresh start.
-
Powdery or Chalky Surfaces on Outside Paintwork:
- Cause: Wearing away of paint film or salts coming out.
- Putting it right: Brush down, apply Weathershield Exterior Stabilising Primer, and repaint.
-
Cracking of Plaster:
- Cause: Common in new houses due to plaster drying out or building movement.
- Putting it right: Cut out cracks, remove debris, fill with an appropriate filler, and paint.
-
Mould Growth on Exterior Surfaces:
- Cause: Moisture promotes mould growth.
- Putting it right: Treat affected areas with Weathershield Multi-Surface Fungicidal Wash and repaint with Weathershield Masonry Paint.
-
Shrivelling and Wrinkling:
- Cause: Drying too quickly, especially with thick coats.
- Putting it right: Allow thorough drying, rub down, clean, and repaint.
-
Rain Spotting:
- Cause: Rain falling on the surface before complete drying.
- Putting it right: Rub down when dry and re-coat.
-
Loss of Gloss:
- Cause: Settling of dew or condensation, especially with high gloss paints.
- Putting it right: Rub down when dry and re-coat in improved conditions.
-
Yellowing on Radiators:
- Cause: Conventional solvent-based gloss paints discolor due to heat.
- Putting it right: Paint the radiator the same color as the wall or use specific radiator enamels.
-
Grey Denatured Wood:
- Cause: Exposure to UV light can make wood grey and friable.
- Putting it right: Remove dead wood, prime with Weathershield Exterior Preservative Primer, and finish with Weathershield Undercoat & Gloss.
-
Rotten Wood:
- Cause: Wood rot due to prolonged exposure to excessive moisture.
- Putting it right: Cut out rotten wood, replace with sound timber, and prepare with Cuprinol and Polycell products before painting.
