Question for builders...

[Supragal]

I need to render the outside of my conservatory (the blockwork obviously not the glass part )

 

I've got a fair idea & google has answered some of my concerns but I have a few questions as I want to make sure I get it right.

 

Anyone here in the trade and is willing to offer me some advice please?

[Homer]

Can't help myself, but JamieP is a good chap to ask.

[Supragal]

Hopefully he will be willing

[JamieP]

[iain2010]

I work for a drylining contractor so send me a pm if you need any help

[Supragal]

Hi Jamie

 

So, this is what I have worked out so far. Correct me if I'm wrong!!

 

You need 2 coats, do the first coat then scratch it up leave it a few days to go off then do a top coat.

 

Can use a sand/cement mix 4:1 but I think in 1 or both coats I need lime or a plasticiser or something? Is that to make it more workable or to make it more waterproof?

 

However, do I put the metal edging beads on before the first coat and not 'fill' them with the first coat or do they go on after the first coat and the second coat covers them to make the corners?

 

How do I fix the edging strips on?

 

I have got edging strips that bend out to put around the bottom above the DPC but I've been looking at other houses to work out exactly where and they all seem to differ. Some have them above the DPC and then are black underneath (I imagine so the water drips off) some seem to start at the DPC and go down to the ground level.

 

Lets work on those for a start

[JamieP]

Yup spot on, use the plasticiser to make it workable, we always put the beads on with the first coat and normally nail them on (galvanised nails;)) put the bottom strip in line with the dpc.

trowel the top coat on and let it set for an hour or so then sponge it up.

Any problems give me a ring 07900 001351

[Supragal]

Thanks Jamie. Do you know if you can you get a ready mixed render that you just add water to? I so can't be bothered to hire another cement mixer.

 

Then I guess bitumen the part under the DPC to waterproof and tidy it up?

 

Think I'll have to no nail or use the mix to fit the strips, theres no way any nail in the world will go into those aggregate blocks, they are ridiculous!!!

[JamieP]

You might be able to get a readymix from wicks/b&q.

 

If its a small job you can mix it in a bucket with a plasters wisk attached to a drill.

 

You should be able to nail into the muck joint or other wise just knock up a small amount of strong cement mix and stick them on.

 

I would use a hammerite paint below the dpc:)

[dangerous brain]

As you have got to put water in anyways to the ready mix you can just mix the separate bits by shovel on a bit of plywood or fairly smooth driveway. The lime is for waterproofing and to make the top coat look better (no-one likes dark concrete look). Be aware you will need to wear rubber gloves when dealing with lime/cement mix or it will literally eat your girly skin right off. Lime is nasty stuff. It initially eats into your skin in every groove in your finger print til it gets to flesh then you quite literally bleed from each groove in your fingerprint as your skin cracks because of the tension in your fingers skin. SO IF I DIDN'T MAKE MYSELF CLEAR WEAR THICK RUBBER GLOVES WHEN HANDLING LIME/CEMENT MIX. You'll need a fairly decent straight edge to scrape back your first coat and get that flat and level to help you get a decent flat finish coat (unless you like the rippled look).

Yup indeed you should use a rough float with a nail stuck about 3mm out of it to key the first coat. You'll get away with a smooth floated lime coat below the DPC. I'm not sure on height but you set the angly drip off piece above the DPC at a height that the prevaling wind does not blow the rain drips back onto the part below it if that makes sense.

 

As far as I remember if the brick was particularly smooth we used to apply a slap on dash of high strength mix cement to pre-first coat key the building

[Supragal]

Thanks for the gloves warning. I always make that mistake. My hands are still raw from yesterdays floor tile adhesive session :/

 

The blocks aren't smooth, they are a really rough texture in themselves plus I need to hide the odd not so perfect bit

 

I've got a plastering hawk/trowel etc so I was going to use those... hopefully they will do the job. That said maybe I should go for a rippled look haha. Got a drill and plaster whisk so I'll check out the ready mix stuff. Fed up with cement fixers

 

I'm starting to get a fear now in case I feck it up massively.

[_Lynz_]

 

I'm starting to get a fear now in case I feck it up massively.

 

Good on you for having a go I get stressed putting together flat pack never mind rendering.

 

Hope it goes ok you certainly sound like you know what your doing

[dangerous brain]

FWIW rendering is the easiest plastering job there is. Its just a bit more physical than hardwalling or bonding inside. You'll be p*ssing in the wind trying to mix a decent strength exterior render with one of them drill jobbers unless you have a decent twin top handled industrial jobber. Its back breaking but shovel mixing for the quantity you want is the best way.