most flexible render

[jacktom]

Hi.
New on this site and would appreciate a little help. After some advice on which silicon based render to go for. Just had an extension built and want to tie in the old with the new. In the process of removing the old pebble dash.Extension is made with dense concrete blocks and original house is brick. My main concern is cracking and would like some suggestions on the best products to use and precautions such as mesh and expansion joints to give it the best chance of not cracking.Thanks in advance for any help given, Tom

 

[Rigsby]

Well don't use Weber Monocouche to start with! Brittle as hell.

Maybe a render with some polymer content fully meshed and a synthetic finish. There are some finishes that are very flexible like Weber's Santane but it cost's a mint.There is also more to it than flexible renders. It is also finding an operative that knows how to apply the materials so they are not in contact with anything flexible like window sills etc.

 

[plasterjfe]

there are different spec levels of anti crack render and cost is always the deciding factor. a great anti crack system for masonry render non insulated is a mortar base of 10mm such as ocr base or hp12 mortar base then a tight coat of polymer base with full mesh then a silicone/acrylic texture

so you end up with 10mm of straight render for depth and level, then a thin coat (4mm ish) of a hi polymer adhesive base with a full mesh cloth embedded , then finished with an acrylic coloured texture preferably one with fibres in it......

installed this a few times on new build spec

 

[jacktom]

Thanks for the advice. Parex seems to get good reviews on here? k-rend sil TC 15? Also, how about expansion joints either side of the window and door on the extension only??? would this help with cracking or just cause problems? Thanks again

 

[Rigsby]

Expansion beads are only good on expansion joints. If you have a straight joint where the extension joins the house then it would be a good idea to fit one there.

 

[jacktom]

Thanks for the advice. Any one recommend a firm or plasterer? Im in staines west london.any one interested got any of there work i can have a look at?