Hi-my elderly mother is having an exterior wall re-rendered on her bungalow. The reasons are cracks in original sand and cement mortar but also internal damp/condensation. The wall is old, brick, with no cavity. The property was extended some 25 years ago and they retained some of the really old walls (for grant reasons as I understand it).
All I have read is that sand and cement render will not allow a wall to breath and therefore moisture will not escape, hence the condensation/damp inside. After doing some research and speaking to a couple of plasterers they said either Lime render or K Rend. We decided on Lime and got quote for that and builder has started (yesterday).
Builder applied scratch coat yesterday but when I went around last night noticed bags of lime but also cement (as well as sand). He was due around today to finish but it's raining so is coming back tomorrow. Anyway, spoke to him on the phone and asked why he was mixing cement in. He said that was right for scratch coat and would be a stronger lime mix (but still with cement) for top coat with waterproofer (PVA I assume). All he seems to be explaining is ways to keep the rain from soaking in but the problem we have is moisture unable to get out.
My problem is, what do I know? So looking for some advice please? They did suggest K Rend as well, but we wanted lime render-my understanding is this should just be a lime and sand mix and needs to be left a decent length of time to dry between coats? Also some cracks in the scratch coat but the builder said that was normal too? Not huge, maybe 1 mm at absolute max.
Any advice appreciated-will meet with builder tomorrow.
Thanks.
All I have read is that sand and cement render will not allow a wall to breath and therefore moisture will not escape, hence the condensation/damp inside. After doing some research and speaking to a couple of plasterers they said either Lime render or K Rend. We decided on Lime and got quote for that and builder has started (yesterday).
Builder applied scratch coat yesterday but when I went around last night noticed bags of lime but also cement (as well as sand). He was due around today to finish but it's raining so is coming back tomorrow. Anyway, spoke to him on the phone and asked why he was mixing cement in. He said that was right for scratch coat and would be a stronger lime mix (but still with cement) for top coat with waterproofer (PVA I assume). All he seems to be explaining is ways to keep the rain from soaking in but the problem we have is moisture unable to get out.
My problem is, what do I know? So looking for some advice please? They did suggest K Rend as well, but we wanted lime render-my understanding is this should just be a lime and sand mix and needs to be left a decent length of time to dry between coats? Also some cracks in the scratch coat but the builder said that was normal too? Not huge, maybe 1 mm at absolute max.
Any advice appreciated-will meet with builder tomorrow.
Thanks.