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Internal window reveals/Fermacell


Russdl

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Further tales along the riverbank.

 

I've had a go with the Fermacell in a couple of cupboards and the spare bedroom with mixed results. It's taking me forever, and when it's more than just me it's taking just a little bit less than forever. I remember reading @Jeremy Harris's blog yonks ago where he mentioned planning the rooms around the standard plasterboard size to minimise waste, I didn't and more's to the point I couldn't in the first floor rooms as we have skeilings and a 2300mm room height to keep the ridge height down. That has resulted in lots of cut's and plenty of waste. I started off trying to get most of the board joints over a stud or noggin, which was a bit of a forlorn hope. I've now progressed to using off cuts behind any unsupported joint, be it vertical or horizontal, (thanks @PeterW) which seems to be the way forward, and makes good use of the offcuts.

 

I tried using resilient bars on the ceilings and walls of the spare bedroom and was disappointed with how many of the board joints didn't end up flush despite both boards being attached to the same resilient bar and it seems the problem is the fancy Fermacell screw (which the Fermacell help line told me was what I needed to fix the Fermacell boards to the resilient bar).

 

About the last 10mm or so of the Fermacell screw is not threaded, so by the time it's gone through the board there is next to no thread to grab the resilient bar, which I believe is the source of my uneven joints.

 

Have I got the wrong screws? The Fermacell screws seem to countersink themselves into the board better than any other I've tried, but does any one know of an alternate screw that would be suitable, with more thread that will ease my boarding woes?

 

Seems like I've got the only Fermacell screws where the whole shank isn't threaded!

 

Here's hoping the filler will do its job.

Edited by Russdl
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Holy Moley, that picture looks like it was taken from my build. Uncanny. MBC passive and internorm perchance? ??

 

I literally did my first wall the other day in the utility room with firmacell (1200x800), installed onto 18mm shutter ply so that made it relatively easy. Onto battens next, and so rises the learning curve. I am happy we went with the smaller one man boards. More to do, but they are easier to stagger with their 1:1.5 ratio and manoeuvre at height alone.

 

Can confirm the screws should be threaded all the way along. The 30mm ones I have anyway.

 

@PeterW why dryfix foam, and not just fix the reveal in place with screws?

 

I'll be getting me some dust cyclones for certain!

 

Anyone try the scorer? I found it to be quite underwhelming, requiring a lot of passes with force to get a deep enough groove in 12.5mm to snap off the peice. Any tricks? Going to get a cheap blade for the saw at any rate.

 

Also for box holes, any good techniques? I've resorted to a recip saw to do the first one, but would prefer something a bit more accurate.

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5 minutes ago, PeterW said:


You can’t screw into a galvanised steel lintel. Timber frame should be easier though if they are timber lintels. 

 

Ah, got you! Mistakenly assumed timber frame. Thanks Peter ?

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2 hours ago, Visti said:

Holy Moley, that picture looks like it was taken from my build. Uncanny. MBC passive and internorm perchance? ??

 

 

Indeed it is.

 

I’ve found the scorer ok but as you say, needs numerous passes. Otherwise I’m using a track saw with a 4 tooth blade, attached to a knackered old Vax (some improvement needed there maybe)

 

2 hours ago, Visti said:

Also for box holes, any good techniques?

 

Im using a jigsaw, seems to be working ok (slowly of course)

 

2 hours ago, Mr Punter said:

As I have previously posted, I think Fermacell is a right bugger to cut and fix. Very clever marketing

 

Noted. I’m in too deep to stop now so wish me luck. 

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@Visti

@Russdl

The router will be your friend. On the downstairs ceilings, when affixing to the underside of the pozijoists, please do yourselves a huge favour and router 3-5 mm squares out of the back of the FC boards where the joists hangers are ;)  
God ( please select as applicable ) help you if you don’t, as sanding back the jumps / humps / bumps on the ceilings where these rigid unforgiving boards have been used, will be a bitch. 

Best of British chaps, 

@Russdl, Chuck those screws in the bin mate FFS !!! If they have no purchase in the resilient bars you’ll end up with cracks and a life of filling and painting ?.

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  • 3 weeks later...

I'd love to report that it's all going swimmingly with the Fermacell and it's a delight to work with but someone once told me that honesty is the best policy, so I won't. Still achingly slow progress, Endless adjustments to the timber frame to deal with; warped joist, noggins that aren't central in the joists, battens that are different depths and so on. Generally its 3 or 4mm I'm fretting over but up to 10 to 15mm in places and as the plan is to finish with the Fine Surface Treatment I think these irregularities will stand out like the dog's.

 

I presume if I'd gone down the traditional route of plasterboard and skim coat then the plasterboard would have gone straight on the frame and the plasterer would have hidden all the minor twists and turns of the timber frame beneath.

 

@PeterW Do you have any smart short cuts up your sleeve that I should be employing to make life a little easier?

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I admit it doesn't leave a lot of tolerance to hide those errors. But 10-15mm?! Damed that stud work sounds like a right nightmare.

 

I've taken to using a mallet to get the noggings into line and in the worst case a plane to shave just a bit off to ensure the bord sits flush with the stud.

 

I also am sanding the joints following joint filler with an orbital sander. First 50 then 80 grain. More work, but the finish feels good.

 

Also found box cutouts are easiest with a 10mm steel drill bit into each corner, and a jigsaw with the Makita B-50 bit to connect the dots. Cuts like butter.

 

Struggling with a multi tool at all... Anyone found some decent blades that'll work on th stuff?

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@oldkettle Typo, I actually meant 'warped studs' but as it happens the bottom of the posi joists are all over the place as well (3 or 4 mm)

 

@Visti The 10-15mm is the exception - but they're there! And yep, I've been using a plane as well. I haven't got round to filling yet, I have that pleasure to come. Have you used any of the FST yet?

 

For the cutouts I'm using a flat wood bit in the corners and a jigsaw, that works well. Destroyed one saw blade already, I don't suspect the jigsaw is far behind!

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6 minutes ago, Visti said:

wait until there's a large area to do

 

Same here.

 

What do you plan on using to apply the FST? Have you got one of those Fermacell spatulas or are you going to be using something else?

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Well, it’s all going a bit pear shaped with me and the Fermacell. Out of time, out of skill etc etc. 

 

Im going need to plaster the Fermacell in at least one room in an effort to get back on track which raise a question from the plasterer which hopefully @PeterW can help with. The question is:

 

How do do you seal the Fermacell boards prior to plastering?

 

Here’s hoping someone knows the answer!

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