External render repair

stewie1098

Hi hope someone can give me a detailed answer here. We have a white washed rendered cottage. Every 10 years it gets painted with sandtex paint. There are quite a few hairline cracks. In the past I have rubbed sealant into these before painting, or channelled them out and filled with mortar- both with varying degrees of success. Should I use painters mate filler- or Homebase are advertising a 'ready mixed' mortar render repair. Probably need some flexibility in the filler- Whats best stuff out there ?
Thanks

brightontraveller

stewie1098 wrote: »

Hi hope someone can give me a detailed answer here. We have a white washed rendered cottage. Every 10 years it gets painted with sandtex paint. There are quite a few hairline cracks. In the past I have rubbed sealant into these before painting, or channelled them out and filled with mortar- both with varying degrees of success. Should I use painters mate filler- or Homebase are advertising a 'ready mixed' mortar render repair. Probably need some flexibility in the filler- Whats best stuff out there ?
Thanks

You need to know substrate, existing render type, age, understanding why/where its cracking, geo etc

What maybe fine for lime rendered cottage in jersey? Wouldn’t be the same as a cottage in the highlands?, Ditto cracking could be age related (300 year old), environmentally effected (on top of a mountain in the highlands~), Result of incorrect render applied to substrate to start with, (sand and cement render applied to fibre board/)

“Homebase “ and alike nearly 99.9 % of products I’d avoid and any advice take its as them having no more knowledge than you ? Go to a builders /paint merchant not a supermarket ?
Without relevant info unfortunately wasting your time asking for a definitive answer,

If you want a guess and a forum you'll get loads I'll start with chase out and sand and cement fill would be correct some of the time ....

road2manchester

Cement based renders will always crack if the substrate wall is damp or single layer. The building has to breath. Re-rendering with fibre mesh over the crack would help but not a DIY job.
I have used K-Rend HPX to fill cracks on an old barn. Its has fibres in it and can be painted over. Go for Acrylic breathable wall paints from places like Decor-8 ( in Bury) they helped me and not had to repaint for 6 years,