Render Surface Guide

We recommend testing your limewash paint colour(s) before application. When sampling on natural, unpainted, breathable surfaces like render, apply the colour to a separate board of the same material or a discreet area that will be covered by furniture. Applying a sample directly to the surface may leave a visible patch in the finished limewash.

If you have a rough surface, a repaired render or a rendered finish you are not satisfied with you can consider to apply a thin coat render with a smaller aggregate size of no more than 0.6 to 1mm on top of the existing render.

Thin coat render is a pre-blended cementitious render with the addition of additives to increase adhesion and improved workability. This will be faster, more economical and a better looking surface than any other method.

For the selection of the right type of thin coat render that may be available in your particular area you should be able to tick all of the following boxes:

☑ is factory blended with additives to aid adhesion and workability and comes ready to use in a bag

☑ is cement based and need only the addition of water for mixing it

☑ is of the right grain size (for internal application we would select between 0.6mm and 2mm maximum

☑ is not water repellant (lime wash paint needs to be able to penetrate it)

☑ is of a neutral colour or grey (not pre-coloured)

Your local building merchant may be able to assist you in the selection of the right type of material. You may also want to consult the Technical Data sheet for the product or speak to the producer.

This type of product is easy to use and very economically. Most EU countries will have several producers of this type of render. With the correct preparation of your particular substrate (surface) you will be able to re-render existing surfaces, including gypsum walls, existing renders and well adhering previously painted surfaces.

If you do this for the first time it is recommended to test the product on a sample area for suitablity at your project location.

In summary, the two most important attributes of the thin coat render you should select for lime wash painting is that it is adhering well and is able to absorb the lime wash paint.


This is what you need to consider when applying thin coat renders:

• Ensure you finished all repairs before applying on coat of thin coat render. Apply to a thickness of around 2 mm, allow some time to cure and use a sponge float to finish. If you like a surface that is smooth to the touch, but still slightly textured use a stainless steal trowel and at the right time push all grains that are proud of the surface back level to the surface.
• Allow to cure and protect the surface from all sorts of contamination, such as grease, fat, oil, wax, but also acrylic gap fillers or paint when painting door surrounds or architraves.
  
• Brush off dust and all loose particles prior to applying two coats of limewash paint. There is no need for any primers or Prep Coat.
• 1 litre of limewash will be enough to cover approximately 7 - 10 m² per application. We recommend two coats of limewash paint for such a surface.

Bauwerk Limewash paint is ideal for raw masonry interiors where it can be absorbed into the walls leaving a breathable surface that is protected by the natural properties of the paint. With no undercoat or sealer required, the process is quick and simple.

Surface Requirements:

Step 1 Brush down the wall.
Step 2 Dampen walls with clean water using a brush or light mist spray to ensure easy application of limewash.

Paint Application:

Step 3 Apply 2 coats of Bauwerk Limewash using a Bauwerk natural fibre brush. Dip the brush into the bucket and flick off excess paint. The brush can hold a lot of paint, but should not be dripping.

Using loose, free strokes, stretch the paint as far as possible in all directions. Maintain a wer edge at all times to prevent colour overlays. Do not leave drips or runs. Continue to stir the paint regularly while painting.

Allow 1-2 hours between coats. When wet, the colour will appear darker and transparent. As the paint dries the colour will lighten and become opague.

Find here specifications and certificates for our paint or watch our guide on how to paint a render masonry wall here or at the bottom of the page

Tip:
With large expanses, it helps to work to a natural break in the wall such as a mortar joint or V joint or with the assistance of another person.
During construction or renovation, it is advisable to schedule Bauwerk painting as the final trade to prevent damage to the final finish caused by other trades or building equipment.

Number of Coats:
Two coats usually suffice.

Weather:
The ideal temperature for applying Bauwerk Limewash is 8°C-30°C (46°F-86°F)
Do not paint if the surface and/or air temperature falls below 5°C (41°F) during application or curing.

External cement render can easily be painted with limewash paint

Surface Requirements:
External cement rendered surfaces should be free from any dirt and dust, finished to the standard that does not require additional coatings (ie crack-free). It also should be free from absorption limiting substances, such as acrylic gap sealers, overspray with other paints etc.


Render Application:
External renders are best applied in two coats to avoid ghosting of the block/brick joints. If the wall is free standing allow for a water proof capping with an overhang.


Paint Application:
You can paint directly on to the cement rendered surface, even if it is still damp.

Should the surface be dry and too absorbent to easily stretch out the paint then dampen the surface sufficiently. Do not thin the paint.
Paint wet in wet (always catch the edges before they have dried).
For large areas ensure adequate scaffolding and manpower.

Number of Coats:
Two coats usually suffice.

Weather:
Paint only with a minimum of three clear days without rain or protect the surface from rain after painting. Do not paint if the wall and air temperature is at 5 deg C or below.

Yes, just follow these simple instructions to paint an interior render wall that has previously been painted.

Surface Requirements

Step 1: Make necessary repairs and remove dust and loose particles. Sand well if the previous paint has any level of gloss.

Step 2: If your previously painted walls have been patched or repaired or have a mix of materials over the surfaces, we recommend sealing over these areas with 2 coats of a water-based undercoat-sealer/primer. If large sections of the wall have been repaired it may be best to seal over the entire surface. Sealing the wall ensures a consistent surface and prevents ghosting of patched areas coming through in the final finish.

Paint Application

Step 3: Apply 1 coat of Bauwerk Prep Coat.

Step 4: Apply 2 coats of Bauwerk Limewash Paint using a Bauwerk natural fibre brush. Dip the brush into the bucket and flick off excess paint. The brush can hold a lot of paint, but should not be dripping. Apply 2 coats of Limewash paint using a Bauwerk natural fibre brush. Dip the brush into the bucket and flick off excess paint. The brush can hold a lot of paint, but should not be dripping. Using loose, free strokes, stretch the paint as far as possible in all directions. Maintain a wet edge at all times to prevent colour overlays. Do not leave drips or runs. Continue to stir paint regularly while painting.

Allow 1–2 hours between coats. When wet, the colour will appear darker and transparent. As the paint dries the colour will lighten and become opaque.

Limewash can be applied over previously painted or sealed exterior walls, but expect a shorter maintenance period. Reduced absorption into the substrate reduces the longevity of the Limewash. However, a simple coat of limewash is sufficient to maintain and restore the finish.

We do not recommend painting limewash over a sealed exterior wall if it's in a highly exposed weather area. For best results over previously painted exterior walls, we recommend applying a coat of a cementitious factory blended thin coat render product before limewashing. This acts as an absorbent layer for the limewash to adhere to on the wall and will make your limewashed wall more durable. The application of Prep Coat is not required for external render applications.

Surface Requirements


Step 1: Make necessary repairs and remove dust and loose particles. Sand well if the previous paint has any level of gloss.

Step 2: If your walls have been patched or repaired or have a mix of materials over the surfaces, we recommend sealing over these areas with 2 coats of a water-based undercoat-sealer/primer. If large sections of the wall have undergone repairs it may be best to seal the entire wall. Sealing the wall ensures a consistent surface and prevents ghosting of patched areas coming through in the final finish.

Step 3: On previously painted exterior surfaces, we recommend applying a coat of a thin acrylic render product/ Acratex Primer before applying limewash. This will provide an absorbent layer for the limewash paint to adhere to on the wall. If limewash is painted over a sealed or non-absorbent exterior wall exposed to the elements, you can anticipate a shorter maintenance period.

Paint Application

Step 4: Apply 2 coats of Bauwerk Limewash Paint using a Bauwerk natural fibre brush. Dip the brush into the bucket and flick off excess paint. The brush can hold a lot of paint, but should not be dripping. Using loose, free strokes, stretch the paint as far as possible in all directions. Maintain a wet edge at all times to prevent colour overlays. Do not leave drips or runs. Continue to stir paint regularly while painting.

Allow 1–2 hours between coats. When wet, the colour will appear darker and transparent. As the paint dries the colour will lighten and become opaque.

Notes + Tips:

Scheduling

With large expanses, it helps to work to a natural break in the wall such as a mortar join or V joint, or with the assistance of another person. During construction or renovation, it is advisable to schedule Bauwerk painting as the final trade to prevent damage to the final finish caused by other trades or building equipment.

Weather

Paint only with a minimum of three clear days without rain, or protect the surface from rain after painting. High-quality, natural limewash needs adequate curing time. This will be longer in colder weather and in humid conditions. The ideal temperature for applying Bauwerk Limewash is 8°–30°C (46°F–86°F). Do not paint if the surface and/or air temperature falls below 5°C(41°F) during application or curing.

Sealers

Generally, we do not recommend sealing outside walls. Our paints perform best when applied to absorbent materials. By not sealing the surface you will be able to easily re-apply another layer of lime wash paint and avoid stripping the wall back and starting from scratch.

The pigments used in Bauwerk Limewash Paints are mineral-based, colourfast and UV stable. This means that our colours are not affected by the sun's ultraiolet rays (which can cause paints to fade). Our paints have been fully tested in the extreme temperatures of Australia and the Middle East.

No, Prep Coat is only for use on internal walls.