internal render

[S a plastering]

whats the best mix for it i was going for 4.1 then 5.1 its on celcon blockwork abou 8m there is a log buner going behind it cheers will it just need damping down done plenty on concrete block but hate thermos inside

 

[church]

is it to be skimmed ? if so one coat of 6-1 will be fine

 

[S a plastering]

yes church an its 25mm thick

 

[church]

if you governed by by thickness do 6-1 then 7-1 might pay you to load the scratch coat with fibres and watch out for the suction when skimming thick render tends to pull in a bit

 

[oasis]

Church you are king of the sand

 

[church]

I had my own pit as a kid ;D

 

[spunky]

why 25mm mate ?

 

[S a plastering]

cos ive got to plasterboard up to the render an all the levels lining through are 25 mm ie socket boxes which are just screwed to the wall not chopped in also door casing which is 25 mm im rendering in the middle of some boarding just so this log burner can go against the render thats what the fire company have spec so thats it

 

[spunky]

ok mate ....the last job i had to do at 18mm thickness included a tyrolean splatter inc sbr the day before we scratched , because of the thickness over those blocks and a poo key might be worth doing mate

 

[S a plastering]

being internal could it not be wba just for that bit

 

[spunky]

yep or you could do that

 

[spunky]

is it compatable with s/c though ???....never tried it meself

 

[napper83]

yes i think it is we scratched the inside of an old outside bog over wba last year and havnt had any problems with it

 

[richardbrown]

I contacted celcon the other day they said the blocks MUST be scratched with a 7-1-1 mix and topped with 8-1-1 !!!!!

 

[spunky]

cant just one coat them then?...............did they say anything about thicknesses?

 

[S a plastering]

was going to do a 6.1 scratch then a 7.1.1 with lime in just for the heat thing then skim

 

[spunky]

i normally use waterproofer in s/c for skimming, if you have to use lime will the w/proofer still work or is it best to go down the pva route?

 

[S a plastering]

i dont normally use waterproofer on small areas like that just feb only doing the lime just to help it flex a bit under any sort of heat i know its prob not nessasery but its on site so might just use a bit

 

[spunky]

it'll deffo help mate

 

[oasis]

why is every using 6-1 7-1 mix fort that was quite week. for people use 4-1 scratch and 5-1 top coat

 

[spunky]

we just make it up as we go along mate ;D

 

[S a plastering]

its not weak with lime in it

 

[S a plastering]

also its internal which doesent need to be dense

 

[bodplasterer]

Plus stronger mixes tend to crack more it dont have as much give but you dont want to make it too weak its all about getting the right balance for the right back ground which is the art in s/c

 

[lucius]

Oasis, what you say about 4&1,5&1 mixes is normaly ok but beware with thermalite, celcon and durox the makers specify a weaker than normal mix. I built some factory units years ago to architecs spec in celcon, all face work the architec spec was 6.1.1. one of the units was for a specialised printer so he had to put dehumidifiers in the unit to bring the humidity down because of the kind of paper he was using the only problem was it cracked the blockwork to F*** anyway big enquirery morter taken to lab etc celcon said morter to strong should have been 8.1.1. since then never trust architecs always better to check your self.
Lucius.