The Great Render PVCu Bead Fixing Debate. | RENDIT


The Great Render PVCu Bead Fixing Debate.

I've not blogged for a while, a combination of idleness and high workload getting our new website and internal systems up and running made me take my eye off the ball but an interesting debate has arisen from our recent invitation to help Alan Titchmarsh and the team on ITV's Love Your Garden NHS Special TV show.

I don't get on site much these days but the attraction of potentially getting my face on the TV made me set the alarm clock 3 hours earlier than usual and head over to site with some of the guys to "render a wall." Our brief was limited, we knew it was a freshly built wall 15-30m2 in size and we knew it needed rendering in 3 days time with only a 9 hour day to do it. Armed with this wealth of information I planned meticulously for all potential outcomes, or so I thought...

We filled the van with boxes of Renderplas beads along with K Rend bonding aids, accelerators, base coats and top coats as they were the manufacturers of choice for the Love Your Garden Team, we were ready for anything, or so we thought!

We arrived on site to damp windy conditions with temperatures of 6c, the signs were ominous. We had about 9 hours to render 30m2, including fitting the beads, not a lot of time for render to set in these conditions ready for scraping we needed to start and start now!

We got the site induction done (30 mins) and spent the next 20 minutes figuring out how we could get the van on the incredibly chaotic tight site entrance full of trades falling over each other to get unloaded. The Ritmo render spray machine and K Rend render materials were literally thrown out of the van as time pressure was mounting. One the guys was sent over to the wall to get clipping the beads whilst we went to solve the next problem. Water.

30 minutes later we had a full 200l drum of water and the Ritmo was close to sparking into life when the question, "How are we fixing the beads?" was asked.

"I brought K Rend HP12 base coat," was my sheepish answer although I was slowly coming to the realisation that we didn't have time for that to set and the lads just laughed that suggestion away

The next suggestion of galvanised nails was also met with laughter as the wall we were working on was still being built in places. Sigh.

We only had one other choice.... Instant Grab adhesive, the solvent type with a colour 50 shades or so less than red. You all know what we mean. We didn't have any, so I jumped in the van to the nearest merchant whilst they got set up. 40 minutes later the beads were fixed and the job just about ready for the application of K Rend K1 Silicone top coat render. K Rend Accelerator was definately needed!

This got me thinking, none of the methods of fixing the beads that were suggested was ideal in this scenario for these reasons:

1) Using Base Coat / Coloured Render to fix PVCu Beads.

Setting times are a problem with this one if you're in a hurry or under pressure as we all are then this causes problems, especially when you factor in that you can't mix up until the van's unloaded and all site services are available.

2) Using Galvanised Nails to fix PVCu Beads.

Some do this but you can end up with warped beads if the nails end up putting pressure on the PVCu render bead itself. Its not ideal on single skin walls either as you risk loosening the masonry with the hammer strikes. The other question is, just how galvanised are those galvanised nails?

3) Using Instant Grab Adhesive to fix PVCu Beads.

On the face of it this seems the ideal method of fixing beads. Solvent based grab adhesives stick quickly and dry in all weathers. We should strongly warn that they are not wthout their risks as they do have a small risk to marking the face of the coloured render if the oils they contain leech through to the surface. This wasn't a huge problem for us for this job as we could have corrected any issues with our Mendrend Render Repair System if it did happen but it could be a big problem for others who don't have the luxury of teams of render repair technicians available at short notice. We did end up using more adhesive than we'd like as the walls needed some, erm, straightening out.

4) Using Render Manufacturer Adhesives to fix PVCu Beads.

It looks like some render manufacturers are attempting to solve this age old problem by introducing their own bead adhesives which I welcome but they all seem to have the flaw that they need mixing on site which means time is potentially lost as nothing can be mixed until the van is unloaded and everything is set up and ready to go. Now, your average plasterers van generally looks like it's been in a car crash in the back, especially if they had a late day the day before. Getting set up and ready the next day can take a bit of time so one man is best getting the beads on whilst the other sets the van, machine or mixing gear up. These types of bead fixing adhesives definately aren't currently ideal in all circumstances either!

So, if you read this article looking for an answer on the definitive way to fix beads, I'm afraid there isn't one currently and it will all depend on the job on the day. We'd advise against using grab adhesives unless absolutely necessary due to the small risk of staining. If their use cannot be avoided try to use as little as possible and minimise exposure of the adhesive to your delicate top coat by keeping it under the bead itself. Big blobs of adhesive are a problem waiting to happen in our opinion.

Hopefully someone comes up with a safe to use quick setting pre-mixed adhesive soon and we can all get cracked on as soon as we pull up in the van! Gone are the days where I'd tinker with solving this problem myself.

The good news is, we been invited back onto the TV to work on another Love Your Garden job so we'll see what we end up using then!

If any of you have questions about this or any other articles please contact us.

Thanks for reading.


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