pebbeldash

[billozz]

i noticed damp...very bad damp in the corner of one of the bedroms, i got up to the side of the house to se if i could find a cause and i discovered the pebbledash at about the same place on the outside of the house was coming away from the wall. as you can see from the picsi have taken the loose stuff off the outside wall ...fairly easy as it was very loose. do i have to take evry bit of render off or do i just go back to the stuff that is fixed to the wall also at the top near the roof (see arrow) what i think should be mortar is just like dust, is it just a case of replacing the mortar, any other info greatly appreciated
thanks
Bill

Untitled

• billozz
• 12 Mar 2011
• 2

[/img]

 

[1john]

Remove any loose of blown render, re point the brickwork and patch in the render / pebble dash.

 

[billozz]

when you say repoint brickwork do i have to rake out between bricks and then repoint and then render

 

[1john]

Only half inch or so, looks like the weather has done it for you.

 

[billozz]

1john,
thanks for your help,
still not quite sure if i have to get all the render off the wall or just take off the lose stuff, also can you tell me the mix for re rendering please, i think im going to have a go at doing it myself, i have done a bit of plastering so think i will be alright, i will be doing the pebble dash again .....only to match up the rest....can you explain how the pebbledash goes on, is there more than one coat of render sorry for all the questions
hope you can help
thanks again
Bill

 

[billozz]

ok ive started to point the wall and am near the point where i need to re-render, not all of the bottom coat.....scratch coat ?.....of render has been removed becausse it seems quite solid.
ive taken off all the loose stuff, do i need re-render with a scratch coat and a top coat,

 

[plstering]

yes

 

[spc]

make sure there is plenty of waterproofer in the scratch coat
leave for a day, then top it with some nice fatty top coat. either tyrolean gun the pebbles on, harl them or grab a hanfull and chuck them at it depending on your lvl of skill or ethics

if you dont use waterproofer the stones will bounce off and make you mad

Scratch coat waterproofer 4 sand:1 op
top coat feb 5 sand:1 lime: 1 op

 

[billozz]

whats waterproofer??

 

[plstering]

its a cement addy you buy it in 5L tubs and add a dash too the mix only in the scrch coat not top coat.
use plastering sant and cement

 

[spc]

(points up)

what he said

if the brickwork is really dusty mix some neat cement with sbr and paint on them first, that way you can assure a good key.

nb, check above the affected area to see where the water is getting in behind the render. Tile overhang, flashing, gutter etc if you can get a few more pics up? ill get a better idea, the bricks and mortar shouldnt have erroded that much without some sort of penetration from somewhere

 

[billozz]

sorry but can you explain what this means please, ive bought building sand and cement to mix the render 4-1 on other advice, is this wrong??

Scratch coat waterproofer 4 sand:1 op
top coat feb 5 sand:1 lime: 1 op[/quote]

 

[1john]

it's mixing ratios mate. 4 parts sand 1 part cement and waterproofer in scratch coat. 5 parts sand and 1 part cement in the top coat.

 

[spc]

thans 1john

golden rule: always have your scratch coat stronger than your top coat (thumbs up) and PLEASE dont forget your waterproofer

 

[roy c]

sorry but can you explain what this means please, ive bought building sand and cement to mix the render 4-1 on other advice, is this wrong??

Building sand is for brick or block work what you need is Plastering sand for outside work..