Rendering over standard house bricks

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Hawk

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Going to be rendering over the outside of some ones house - the brick is in good condition, but have been wondering about the best way to form a good key for the render - as the pointing is in good condition its not going to be that easy to knock out some of it - would using an angle grinder be a good idea? i.e. in the joints and across the face of the bricks, Don't want to be up a ladder for a week with a hammer and chisel! Also going to be using a sand, cement, lime mix. Cheers.
 
would i then put a scratch coat on and then the top coat - or just go straight on with the top coat?
 
been rendering for years with weber sto etc always use rendaid great stuff make sure you key the rend aid i dab with old brush head
 
mix sbr with cement and some sand and teyolene the brick. make sure you cover all windows and clean all plastic and tools perfectly as it will stick like s**t to a blanket
 
Sorry mate but why would you want to hack the old pointing out if it is sound, do you realy know what you are doing?
Lucius
 
I guess he is trying to find a key for the new render, take out the pointing = key for new coat but a right royal pain in the ass. Do as I said above then leave it and scratch coat next day and stick up beads
Rich Brown
 
if theres a high lime content/weak mix in the joints will a sbr s/c splatterdash get over this or will it still pull on the joint?
 
if your worried about to much pull then I would get the hose out give the bricks a good drink, when they have had their fill have half an hour for some snack to let the surface dry a bit, then get the roller out and roller sbr over the brick to kill all suction ,wait until tacky then apply your sbr s/c splatterdash, then clean up and go home. next day scratch coat and fix beads next day whilst green top coat.

Whats your opinion Spunk y ??

Rich Brown
 
by te book mate ;)......do you use waterproofer in youre scratch coat after applying an sbr base?
 
If its winter then I just use a Plasticiser so the top coat has a chance but if in summer then yes i add waterproofer to the mix so it doesnt go of toooo quick.

Rich Brown
 
If we are talking about a 9inch wall built in lime morter you shouldnt be doing any of this, SBR and waterproofers will stop the wall from breathing idealy should be lime putty render.
Lucius
 
then like luscious is saying its a different can of beans .........richard do you find youre top coat sticking to the straight edge when using sbr in the base coat?........im tempted to use no w/proofer in the base coat so i can rule it off
 
sorry spunky I dont really understand what you mean mate.

I dont use sbr in the scratch coat only the dash coat as a key then scratch and top as normal.

Rich B
 
what i find is if you use sbr as a stibble/dash/slurry coat and ad waterproofer to the scratch coat theres no suction and when you rule off the top coat the gear just wants to stick to the straight edge .......dont know might just be my technique ......
 
sounds like your mix isnt mixed as well as it should be resulting in heavy crud .... let it mix for as long as you can so its light and easy to use. Use a H frame rule or a rule with a fine edge to it rather then a rounded edge, make sure your scratch coat is scratched properly or its all just slide off the wall.

any of the above or some other problem do you think Spunky ???

Rich b
 
Richard thats what ime talking about a house built of 9 inch brickwork in lime morter.
Lucius
 
Lucius,

He is not talking about a lime house he is wanting to know how to get a good key for his sand/cement/lime mix laying up over smooth brick work and going on that basis i have supplied my answer.

Rich Brown
 
Hi Richard as far as i can see Hawk has never mentioned the brickwork being smooth but i may have missed that what he did say was that it was pointed against being jointed which indicated to me that it might be an older house built of lime morter if that is the case SBR or waterproofers are not sutible.Depending on the brick most walls do not need preparing just a good soaking is enough.
Lucius
 
Again this is another example where we need a full description of the job in hand to give proper advice on what to do.

Yes it depends on the brick some in my opinion are fine with just a drink, others I feel need a key.

Also unless the house is an old cob building with REAL lime morter used between the stones and REAL lime render used on the walls there is nothing wrong with using a 5-1-1 render. I have used LIME render a lot on heritage houses which I would agree needs it but they and houses like that make up a very small portion of the market.
In 99% of rendering jobs there is nothing wrong with using sbr to seal the building and to use it as your key.

Rich Brown
 
if the house is a cavity contruction and there un-painted sand faced commons bricks sbr slurry & 2 coat render.
 
Hard to say mate tbh depends on the age of the building etc the hurling and nhl route has to be considered or opc render but it depends on what you consider is best for the building but both a permiable just to different degrees
 
I would consider using both sand / cement or lime render depending on the age of the building, but i would prefer to see the job first ;)
 
Whats the difference between a house built of solid brick in lime morter 200 years against one built yesterday with the same method? Answer is nothing, it is not the age of the building but the way the building is built that determines what render is aplied.
Lucius.
 
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