Render Troubles.......

[Rawdon51]

Hi - newbie to this forum. Apologies for the long post - wondered if anyone can help?

Our house altertions have called for us to render the rear elevation (fairly large 2 storey, 5 window openings including 1 folding-sliding doors @8ft downstairs, 1 french windows @ 4ft upstairs).

Take 1: Complete cowboys, k-rend onto bare block. They put in on in 1 coat, scraped immediately (rather than after 24 hours) causing the worst finish you've ever seen, put it on too thin so all block joints were visible through, then ran out half way through saying they'd come back to finish it off (...anyone predict big visible joints?..). Needless to say, we told them not to bother. Only upside, it was the builders men - and money - part of a fixed price contract. Several days of hacking off (for the builder) later, onto take 2.....

Take 2: Scared off from k-rend, chose to go with traditional sand-cement render. Put on in 2 coats (scratch, top). Looked ok on first inspection. Once the sun shone in the right (wrong?) direction though, very uneven finish. Worse, after a couple of weeks, small cracks appeared spanning out from the corner of several openings, and a couple of patches seemed "blown" - hollow when you tapped on them. These were the patches we could see and reach of course, don't know about the rest. The builder returned and cut out the cracks & blown areas, patching in. Now after another couple of weeks, some more hairline cracks are appearing from other openings, small cracks in the patches themselves, and one of the "blown" areas still appears to be blown.

We now have a choice.

Do we carry on as planned, ignore the bumps & cracks & hope Sandtex high-build (decorator recommended) will by and large cover the imperfections?

Or do we have another "chat" with the builder and point out this is NOT the norm for render, that maybe he should have used mesh reinforcement around openings (..recommended in one of the quotes we got...), get it sorted and forget about painting for now.

We're reluctant to start hacking off AGAIN, but if it needs to be done, it needs to be done. Then again, maybe we're making mountains out of moleills - we don't know having not had render before (...and won't plan on doing so again!).

Any advice gratefully received.

Jon

 

[Rawdon51]

Take 1:

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[dazdel]

Hi mate,
First, they did not know what they were doing with the k rend or
the s@c. A job this size would be a days work for a plasterer and a
lab. Looks like they even did the s@c in 2 sections, which tells me lack of experience, or cowboys as you said. If it was me i would get the builder to remove the lot again, and find a real plasterer. Did they use waterproofer
in the scratch coat, and what mix did they use for scratch and top coat ?.
You want something like, 3.1 scratch,with water proofer and 5.1 top coat
Others will give their opinions on mixes etc i'am sure, and they all work,
just down too the person doing the job.

 

[dazdel]

P.S Did they arrive on horses

 

[roy c]

Tell your builder that the finish that they have produced is not acceptable and you are not happy with it and they obviously cannot render!!!! Get a reputable plastering firm in to come and have a look and they will tell you that is not how a sand and cement rendered finish should look like .Dont whatever you do let them put any paint at all on it. That will not cure the mess they have made only cover it up, while they get on their horse's and ride off with your money never to be seen again.. Repeat dont let them put any paint on it!!!!!If they cant get it right after 2 goes I would not give them another chance. You deserve a proper job done that you are happy with,so dont give in to them and if it is the same decorator doing your decorating that said. " it would be ok with high-build on it " doing your decorating I would get rid of him aswell!! Hope this helps.The customer is always right Good Luck.....

 

[Micilin]

Just a few bits from me.



First of all, please don't let this put you off render!

If you bought a car that broke down and cost you money, you would not promise never to drive one again, or if your windows were badly fitted, you would not brick them all up and say goodbye to glazing!

That said , you have had a terrible experience and my sympathy. Where did you get these lads from, or are they the builder's regular spreads? Ask to look at the work of whoever comes to sort it out.


Anyway you would have to hack off anything that is loose, this is vital. You could leave on anything that is sound, but you would need to key it with an SBR slurry.

I would be concerned about the cracks from the openings as this suggests structural movement rather than the render. Is it a new elevation or new windows ?

These openings can be meshed to reduce cracking. I mesh 500mm band around openings as a general rule. However, if you get big movement in a building you will get cracking somewhere if you do not have control joints.

I hope you do get it sorted with the minimum of fuss and it should not cost you to put it right if the builder has got those shower in .


Couple of points about K- rend as an aside-

It can be done in one coat by machine (and indeed this is the way it should be done 'Mono Couche' - One Coat) but doing it by hand means two coats to get the required thickness.

It must be scratched back same day in warm weather( next day in cold weather) other wise you cannot finish it properly. Judging this is part of being a tradesman.
[/b]

 

[Rawdon51]

Thanks very much to everyone who has taken the trouble to reply so far. Yes, "yee-ha"'s and riding off into the sunset abound here! The renderer was sourced by the builder who has been working on our house for the last 18 months (as were the k-rend guys...), so we have recourse to him, but after failing to get the job done on the first 2 attempts, we're trying to be a little more proactive this time.

Below are a few more pictures of the work, including some of the patches, which are themselves now cracking around the edges and in their centres. Additionally, tapping on the render with a hammer has revealed several more small "blown" patches.

Ref. the elevation - yes it is entirely new, so I would think some small amount of settlement would not be unexpected?

So we've now had someone who we believe is a professional renderer visit. His opinion is that the job is probably "70%" OK, and probably what would be expected of a job done by a skilled internal plasterer who has turned his hand to rendering. He is advising not to hack it all off, and says this would be expensive for a job that is not horrendous (2 men, scaffold, a week, a skip...).

He is proposing "elastomeric" coating may be appropriate, and says he has worked with both Protex (cheaper) and Liquid Plastics Monolastex (Rolls Royce) previously. We don't like the samples of the "normal" texture he showed us, but the "fine" (not smooth) does look quite attractive (esp. the monolastex). He says that although this will not give a 100% seamless finish, it should cover most of the uneveness, as well as providing a protective coatin that will flex with any movement and resist cracking, including 15 year guarantee (etc. etc.). Including remediating the small patches of blown render - which he proposes to do - he is quoting in the order £1800.

What do you guys think of this approach, and the price? Are we lurching from one disaster to another?

Thanks again.

Jon

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[joe-90]

That's 'hor-render-ous. I can't see anything sorting that lot our. I'd be amazed if you got it 'sorted' and never had any further bother. If this new bloke thinks that is the work of a skilled plasterer I'd look in his van for his Stetson and Colt 45.

Don't rush into anything. If it's blown - it's got to come off (sooner or later it will).

 

[roy c]

I'm sorry but I have to agree with joe on this one...

 

[dazdel]

Hi rawdon, you say you had a professional renderer look at it, there is no such thing as a renderer. A plasterer yes, alarm bells ringing for me.
Sounds like a lot of money for what he is going to. You could remove the
hollow areas and patch up, then tyrolean the lot. Sure this would be
cheaper than 1.800. Agree also with the above, Find a local plasterer, someone who is established in the area.......If it was my own house i
would take the lot off, and start again. prob days work 2 men with kangos
to remove. your'e not paying, so get what you want.
They ballsed it up

 

[Rawdon51]

Thanks guys.

If the scratch coat they put on was sound against the blockwork, but it was just the finish coat that has blown, would it be possible to remove the top coat & leave the scratch coat. Or is it better (or just as easy) to get all the way back?

Also you mention tyrolean...what's that?

 

[moonman999]

Sand and cement renders........ typical



Seen in France a decopierre lime based limestone mixed with marble. breathable two coat system that will nor bloom or peel.10 years warranty and through coloured.
Europeans, what do they know. eh???
Horses for courses