Wall Rendering

[dorothymeta]

Whats the best way to clean a mustard coloured rendered wall. Thought about pressure washer but a)will it take the surface off and b) I will need scaffolding to pressure the top of the house?
Any ideas welcome as it looks really scruffy in parts.
I've been told it is not paintable, is that right?

[tonyav]

Why is it not paintable, dorothymeta ?. Our house has rendering and it is painted.

[ummmm]

Same as Tony.

[SirOracle]

I also agree with both posters.

It may however require a couple of coats.

[tonyav]

By the way, don't use a pressure washer on it, it will most probably damage the rendering.

[Maydup]

Our house is rendered and we've painted it a couple of times. We used external textured masonry paint and a heavy duty roller. Or you could have it sprayed. It was fine.

I don't think you'll clean it although a contractor might have a product to use. But by the time you've scaffolded it or used access equipment, you might as well have it painted.

[The Builder]

The question is ... is it paint or coloured render?

If render, then a scrubbing brush and bleach. Only use a pressure washer if it's fairly recent sand & cement render.

If it's an older house with a lime render, then no pressure washer.

Anything is paintable with the right preparation. Firstly, try a small area with a good scrub. See how it comes up.

From your description, it sounds like a gable end. I can't answer the scaffold question without being there. If an experienced decorator thinks he can handle it with towers/ladders, then he'll do so. Scaffolding isn't always necessary.

[dorothymeta]

It is coloured render applied when house was built in 1904. I think is why I was told it couldn't be painted. I believe once painted it may need doing every 5 years? could be expensive?

[The Builder]

Edwardian roughcast , Dorothy. (lumpy finish). This was often done with a lime mix. Probably not coloured. What you're most likely seeing is the colour of the lime/sand itself. Often it was finished in limewash (lime used as a paint.)

Either way, that's the colour lime tends to go in time. For it to have survived this long, it probably had ordinary cement added to the mix. Roughcast with or without cement were both common at the time.

I wouldn't risk a pressure washer. Simple scrubbing with a little bleach.

For painting... a couple of coats of limewash. Modern exterior paints would easily go on, but may cause problems with the breathability of the structure if it's a solid wall construction (no cavity.)