Cement render with membrane paint vs acrylic render

tweety123 · Sep 07, 2019 6:12 pm

I'm building a new house, which has double brick exterior walls and will be rendered.

I am given two options for rendering the walls:
Option 1: cement render then high performance membrane paint
Option 2: high build render with acrylic render

Appreciate if anyone could help me understand which option will last longer and require less maintenance. Option 1 is significantly cheaper than option 2, but the house is my long term family home so I will take the option that gives me better quality and less maintenance in the long term.

Mirrmu83 · Sep 08, 2019 12:33 pm

Hi Tweety,

I will assume in Option 2, that acrylic render means trowel-on pre-tinted Texture Coat

In both options, the cement render and high build render is typically a cement & sand mixture used to level surface, hide bricks etc. which is applied 5-10mm in thickness.

For Option 1, this is normally sponge finished to provide a reasonable finish ready for paint. In Option 2 the finish is of a lesser quality as it gets a trowel-on Texture coat over it.

In both options the final finish is a "paint" product.

The "acrylic render" will stain very easy, mark easy and is difficult to repair, will fade, get dirty etc.

The high performance membrane paint will provide a surface which stays cleaner, easy to repair, doesn't fade as much, recoated (painted) easily.

thnks

tweety123 · Sep 08, 2019 2:50 pm

Mirrmu83

Hi Tweety,

I will assume in Option 2, that acrylic render means trowel-on pre-tinted Texture Coat

In both options, the cement render and high build render is typically a cement & sand mixture used to level surface, hide bricks etc. which is applied 5-10mm in thickness.

For Option 1, this is normally sponge finished to provide a reasonable finish ready for paint. In Option 2 the finish is of a lesser quality as it gets a trowel-on Texture coat over it.

In both options the final finish is a "paint" product.

The "acrylic render" will stain very easy, mark easy and is difficult to repair, will fade, get dirty etc.

The high performance membrane paint will provide a surface which stays cleaner, easy to repair, doesn't fade as much, recoated (painted) easily.

thnks

Thank you Mirrmu83. The acrylic render in option 2 is products such as Dulux Acrylic Texture or Rockcote Sandcote HYDRATECH to be applied on top of a high build render. The brickwork of my exterior wall is uneven. As a result, I was advised using acrylic render will help level the walls, prevent cracks and is easier to maintain in the long term as the thickness of acrylic render can get up to 15mm. The costs is significantly higher compared with option 1 so I'm trying to understand the pros and cons before making my decision.

Mirrmu83 · Sep 08, 2019 9:21 pm

The high-build render is used to level the walls out. They are cement and sand mixtures with an acrylic component (like 1-2%) and normally a polystyrene ball in them which creates the “high-build”. These coatings do not stretch like a rubber band or bridge cracking.

The Dulux Acrylic Texture (mainly Coventry Course) is applied 1-2mm thick, its a finishing coat which puts the desired color on the house and provides a very neat and tidy finish. Most companies like Dulux, Rockcote, United etc will still specify a membrane/paint on top of this to get full warranty and true colour.

For instance, if a few rust spots appeared on your wall which was not painted then manufacturer would not cover.

The only way to prevent cracking is to install expanded metal sheeting or embed a fibreglass mesh into the render at time of rendering.

It is not possible for the Texture Coat to be easier to maintain than the membrane/paint. It’s a slightly porous system, it will stain, take in moisture, get dirty etc

tweety123 · Sep 08, 2019 10:03 pm

Mirrmu83

The high-build render is used to level the walls out. They are cement and sand mixtures with an acrylic component (like 1-2%) and normally a polystyrene ball in them which creates the “high-build”. These coatings do not stretch like a rubber band or bridge cracking.

The Dulux Acrylic Texture (mainly Coventry Course) is applied 1-2mm thick, its a finishing coat which puts the desired color on the house and provides a very neat and tidy finish. Most companies like Dulux, Rockcote, United etc will still specify a membrane/paint on top of this to get full warranty and true colour.

For instance, if a few rust spots appeared on your wall which was not painted then manufacturer would not cover.

The only way to prevent cracking is to install expanded metal sheeting or embed a fibreglass mesh into the render at time of rendering.

It is not possible for the Texture Coat to be easier to maintain than the membrane/paint. It’s a slightly porous system, it will stain, take in moisture, get dirty etc

Cement render sounds the right option for me then. Thank you so much. Glad I don't have to go for the significantly more expensive option.

chippy · Sep 09, 2019 12:18 pm

Acrylic texture coat is superior to standard painted cement render.
It is far more resilient regards cracking and movement.
Basically both systems use floated sand and cement at roughly 10mm over the brick work.
For painted render that is then sponged to get a smooth uniform finish for painting.
If it's going to have acrylic texture applied the float is just screeded flat. It's allowed to dry then an acrylic primer is painted on then acrylic texture is trowelled on at around 1-2mm. It has far more ability to expand and contract compared to standard paint. It also has more depth (texture) to the finish due to the nature of the coating.
You do need to be careful with acrylic texture because it is very hard to patch. You often need to retexture the entire wall to get a seemless finish.
It costs more because it is far more labour intensive but if you look at houses around 10 years of age a house with texture coat will still look good whereas a painted render house will be looking pretty ordinary and will be needing another coat of paint.
There is a reason all high end homes utilise acrylic texture rather than painted render.

tweety123 · Sep 09, 2019 9:51 pm

chippy

Acrylic texture coat is superior to standard painted cement render.
It is far more resilient regards cracking and movement.
Basically both systems use floated sand and cement at roughly 10mm over the brick work.
For painted render that is then sponged to get a smooth uniform finish for painting.
If it's going to have acrylic texture applied the float is just screeded flat. It's allowed to dry then an acrylic primer is painted on then acrylic texture is trowelled on at around 1-2mm. It has far more ability to expand and contract compared to standard paint. It also has more depth (texture) to the finish due to the nature of the coating.
You do need to be careful with acrylic texture because it is very hard to patch. You often need to retexture the entire wall to get a seemless finish.
It costs more because it is far more labour intensive but if you look at houses around 10 years of age a house with texture coat will still look good whereas a painted render house will be looking pretty ordinary and will be needing another coat of paint.
There is a reason all high end homes utilise acrylic texture rather than painted render.

Thanks Chippy. Good to know more about what Acrylic render has to offer. Will help me see the pros and cons of both options before I make my decision.

kester · Sep 11, 2019 12:27 pm

Is there any difference to acrylic render finish/texture?

How to maintain this type of render? Another paint coat?

Mirrmu83 · Sep 12, 2019 8:33 am

Most “texture” manufacturers will require you to paint the texture to achieve their full system performance and product warranty.

Texture is applied to budget houses to expensive houses,, very few are painted and will have no warranty for rust spots, staining, true color etc

If you choose a Dulux colour it cannot be replicated by Rockcote, Unitex or Macrender Texture. The differences can be quite significant.

Maintenance is quite simply cleaning the wall with warm soapy water, broom surface and hose off. Avoid high pressure. Some staining you will not get out as its a porous surface to begin with.

To fully update your wall surface you would simply paint it, you would not reapply “Texture”.

Products like Weathershield, Solarguard, Acrashield are very good products.