External Wall Insulation preparation

[fletcher5555]

Evening All

 

I am researching external wall insulation and have learned so much from the posts so thank you to all who have contributed. 

 

I have an 1800 cottage which has been extended in the 1980's. Externally the cottage is painted white directly onto brick (no render) which is flaking off in some places but looks pretty good in others. It looks like this paint is non-porous but there isn't any damp in the walls, only a little bit from the floors of the older parts of the cottage. 

 

My question is should this paint be stripped before the EWI insulation is fitted? If it's not removed would this not increase the likelihood of damp given that moisture won't be able to flow out from the house? Lastly, if I do need to remove the paint can you provide any advice how I can do this as I doubt a wire brush or paint stripper would work?

 

Thank you all for your help. 

 

 

[tonyshouse]

Sand blast paint off , bit messy and will do it, prone to etch bricks and pointing. 
 

needle gun is a possibility but bit laborious 

 

if it was mine I would scrape off loose stuff, rake the joints hoping to find lime mortar, sadly unlikely then not remove paint 

 

I would go 200mm EPS with breathable render.  If non breathable insulation you run risks but dewpoint will be in the very outer surface of the EWI in winter 
 

 

[nod]

I’d just go straight over it 

We go over old render that has been painted or sealed with other coating