What to use for rendering...

[ray316]

Hi guys, l'm set to render the outside wall of my house as alot of the render on one face of the house has alot of the render blown and coming away.. So l would like to know what is the best render material to use, will sand and cement be ok or these mixed render bags you can get from wickes and b&q...
Is it waterproofer that l put in for the scratch coat but nothing in the top coat and how long to leave between coats..
Also what beading will l need for corners of the windows and door ..
When l start rendering the walls where is it best to start higher up or from the ground and work up...
Will l need to treat the walls before the scratch is applied..
Thanks

 

[thatbloke]

what kind of house do you live in?

 

[roy c]

I think if you need to ask these questions then it might be better to get someone who knows what they are doing to render your house. It's not just a matter of being told what materials to use and what goes in the scratch coat and what to put in the top coat but what you cant explain to people is "experience". Sorry if this sounds a bit harsh but rendering is a skill that comes with experience and it's not just a thing you can just do...

 

[roughcaster]

I think if you need to ask these questions then it might be better to get someone who knows what they are doing to render your house. It's not just a matter of being told what materials to use and what goes in the scratch coat and what to put in the top coat but what you cant explain to people is "experience". Sorry if this sounds a bit harsh but rendering is a skill that comes with experience and it's not just a thing you can just do...

Very true Roy!!!

To answer one or two points raised,,,,
I wouldn't use the mixed render bags from Wickes/B.Q you mentioned, i'd mix my own.
I never use any corner beading for render, but that is my personal choice.
You do put waterproofer in the scratch coat, but you must be very careful to use the correct ratio.
Always start from the top and work down, that way, you're working up and into what you've put on.
It's alway advisable to give a block/brick wall a wet down before you start scratching, especially if there's suction.
I normally scratch a wall, and then if possible, leave it to set and cure for a day or 2. When you're ready to put on the top coat, give the wall a wet down, let it drain off, then put on the top coat.

As Roy said, rendering is a skill that takes a lot of practice. You've to know the mix, application, how to handle the tools, knowing at what state the render is at for finishing, how the wind/sun can affect the progress for finishing etc.
It's a good idea to practice on a smaller area that you can take off if things don't work out. Although rendering's not rocket science, i wouldn't advise a beginner to try it on any large/ish area, unless you're sure you can make it. Good luck to ya anyway.

 

[ray316]

what kind of house do you live in?

The house is concrete/stone walls, l think these houses were built in the 50's and if l'm correct they put exterior shutter boards of some kind up and these were filled with concrete/stone which are a pig to drill from inside the house as your drill bit either snaps or never drills straight.
Anyway roughcaster just wondered why you would never use...
Mixed render bags....which would you recommend
Never use any corner beading for render ..What do you use for corners ..

Anyway chaps l've done little bits of plastering in the house before and thought l would give it a go before phoning the professionals in... you never know useless you try do you ...

So any tips and advice most welcome....

 

[roughcaster]

what kind of house do you live in?

The house is concrete/stone walls, l think these houses were built in the 50's and if l'm correct they put exterior shutter boards of some kind up and these were filled with concrete/stone which are a pig to drill from inside the house as your drill bit either snaps or never drills straight.
Anyway roughcaster just wondered why you would never use...
Mixed render bags....which would you recommend
Never use any corner beading for render ..What do you use for corners ..

Anyway chaps l've done little bits of plastering in the house before and thought l would give it a go before phoning the professionals in... you never know useless you try do you ...

So any tips and advice most welcome....

You're quite right to give it a go Ray, that's the only way to learn.
I have never used the mixed render bags, i prefer to use a local washed plastering sand, which i have used for years. It comes from a local sand quarry. The colour is constant (pale), plus you can get any amount you need, say from a lorryload, to a half a dozen bags, to a couple of bucketfulls. I find the colour/s of the sand that's sold in Wickes,B&Q etc, can vary a lot. This can affect the finished colour of the render etc, so that's why i don't use it.

Why do i not use beading for corners on external rendering?

I never have. From day one, (in the 60's) i was taught to form a corner/s using a batten. This batten can either fixed temporarily, and then returned some other time, window reveals etc, as in roughcasting,, or you can form a wet returned rendered corner, by moving an un-fixed batten from one wet face to another, removing it as you go. This method was also used externally/internally long before corner beading as we know it, became popular.
Anyway,,, i prefer the look of un-beaded external corners in render outside, but that's just my preference.

By the way, the building method you refer to, (concrete/stone walls) is called "no fines concrete". Wimpey the builders, along with other companies, built many structures that way from houses to blocks of flats.

 

[stevethespreader]

just wondered why you would never use...
Mixed render bags....which would you recommend
Never use any corner beading for render ..What do you use for corners ..

So any tips and advice most welcome....

rendering is a science, such as choosing the sands, mix ratios, colour, additives if needed ect, you will not get all that from a ready mixed bag from wickes
for example if you want a 4-1 for the scratch coat and a 5-1 for the float coat how are you going to manage to do that with it already mixed?

 

[roughcaster]

just wondered why you would never use...
Mixed render bags....which would you recommend
Never use any corner beading for render ..What do you use for corners ..

So any tips and advice most welcome....

rendering is a science, such as choosing the sands, mix ratios, colour, additives if needed ect, you will not get all that from a ready mixed bag from wickes
for example if you want a 4-1 for the scratch coat and a 5-1 for the float coat how are you going to manage to do that with it already mixed?

Good points raised there Steve.