Internal window reveals/Fermacell

[Russdl]

I'm having a go at this dry lining, and contrary to most advice I'm using Fermacell (all previous comments re Fermacell are spot on, I'm using 1200x1200 boards)

 

I've been making all my mistakes in a walk-in wardrobe where they won't be easily seen and have now ventured into the spare room to see what more mistakes I can make in what will be a seldom seen room which leads to my question.

 

We have inward opening windows. The airtight tape is fixed to the timber frame and wraps around onto the window frame by about 30mm. The gap between the internal reveal and the inward opening casement is about 50mm. 

 

It looks to me like it's going to be difficult to get into this space between the reveal and the inward opening casement on the hinge side. A bit of plywood packing first so that the Fermacell will hide the tape should do it but then how do I get the FST on to the Fermacell or, indeed, paint it, on that hinge side. Is there a simple way? Alternatively I guess I could line the reveal with timber that is finished prior to fitting?  Easy to say...

 

 

 

[Carrerahill]

20 minutes ago, Russdl said:

I'm having a go at this dry lining, and contrary to most advice I'm using Fermacell (all previous comments re Fermacell are spot on, I'm using 1200x1200 boards)

 

I've been making all my mistakes in a walk-in wardrobe where they won't be easily seen and have now ventured into the spare room to see what more mistakes I can make in what will be a seldom seen room which leads to my question.

 

We have inward opening windows. The airtight tape is fixed to the timber frame and wraps around onto the window frame by about 30mm. The gap between the internal reveal and the inward opening casement is about 50mm. 

 

It looks to me like it's going to be difficult to get into this space between the reveal and the inward opening casement on the hinge side. A bit of plywood packing first so that the Fermacell will hide the tape should do it but then how do I get the FST on to the Fermacell or, indeed, paint it, on that hinge side. Is there a simple way? Alternatively I guess I could line the reveal with timber that is finished prior to fitting?  Easy to say...

 

 

 

As I type this my plasterers are working on our build, I finished the reveals on Monday morning about 02:00! We were using plasterboard but the principle is the same, 11mm OSB packers to float the board over the window brackets, sealed to the window frame then PB over the top, plasterers did all the reveals and small bits first, I think they just ran their trowel in and also were using a small end-handled trowel which basically looks like a mini trowel with a cranked handle on one end so that as much as 6-8 inches of it could be slipped into tight spaces, the reveals looks great. 

 

For painting, I am sure I will manage, masking tape may come in handy!

 

 

[Russdl]

@Carrerahill Thanks, are your windows inwards opening as well? I suspect the Fermacell Fine Surface Treatment can be applied in much the same way as your plasterers did your reveals.

[Carrerahill]

29 minutes ago, Russdl said:

@Carrerahill Thanks, are your windows inwards opening as well? I suspect the Fermacell Fine Surface Treatment can be applied in much the same way as your plasterers did your reveals.

It is a mix from room to room to be honest, but we have a similar issue with some of them and I did note the reveals were getting close at some points.

 

Another option may be for you to trim your tape back? 

 

If it was me I would pack out a little, board it, then use a fresh blade and cut down the tape at an inward angle, then by the time you FST and a bead of silicone/caulk etc. down the seam (as FST/Gypsum etc. always crack at interfaces to wood/uPVC etc.) you will hide any light mark to the window frame. Alternatively if you lightly score the tape will it tear cleanly along the score?

 

 

[Russdl]

19 minutes ago, Carrerahill said:

a bead of silicone/caulk etc. down the seam

 

That would be the plan, if I can get in there.

 

20 minutes ago, Carrerahill said:

if you lightly score the tape will it tear cleanly along the score?

 

I'm not sure how willingly the tape would let go of the window, I'll give it a try in the morning.

[Russdl]

Another 'window reveal using Fermacell' question. What about the internal 'outside' corners of the reveals? Another area that I can't find any guidance on. 

 

As the Fermacell should just be finished off with a bit of filler and then the FST (without any beads as far as I can tell) I'm assuming the outside corners of the reveals should be finished as in 'A' below and not as in 'B'. Have I got that right?

 

The various colours are to hopefully make things clearer, green being the internal face of the timber frame.

 

[nod]

It would be a lot neater and easer to finish and paint if you tacked a  skim stop on the PB face butted against the window frame 

[Russdl]

18 minutes ago, nod said:

It would be a lot neater and easer to finish and paint if you tacked a  skim stop on the PB face butted against the window frame

 

Good idea, thanks for that.

[ProDave]

Don't forget to cover you hinges in masking tape to keep all the sealant, goo or whatever off them.

[Russdl]

19 minutes ago, ProDave said:

Don't forget to cover you hinges in masking tape

 

Happily the hinges are hidden so that won't be an issue.

[PeterW]

B is correct in your picture. Cut the Fermacell slightly over sized and finish with a bearing bit in a cheap router running over the face. You may need a small fine tooth saw to square off the corner. 
 

You can snap and score the reveal boards to fit with the rough edge on the inside of the routed edge, then just fill any gaps. Leave a 2mm gap from a factory edge to the frame and FST and paint the boards then finish with a bead of decent sealant between the board and the frame of the window. 

[Russdl]

@PeterW I was hoping you'd be there Peter ?

 

And the answer is 'B' bloody glad I asked the question! I was going to plough headlong into 'A'.

 

I've got the cheap router and probably a bearing bit (what ever that is) but how exactly do I run the router over the face? Attach a temporary batten to the face first??

 

I think I've just learnt about 'bearing bits'. 

Edited January 7, 2020 by Russdl
been to you tube school

[PeterW]

Also worth using decent extraction and a dust cyclone when cutting, routing or sanding Fermacell as it’s evil stuff.  The dust gets everywhere and even through filters on hoovers and you destroy the bearings. 

[Russdl]

11 hours ago, PeterW said:

when cutting, routing or sanding Fermacell as it’s evil stuff

 

Oh yes.

 

I had a go at that ‘routing round the reveal today’! You definitely need the bare minimum overlap to rout if you don’t want to disappear in a cloud of dust, though the finish does seem to be spot on (only tried a wee bit so far). 

 

Today has been 1 step forward, 4 steps back but without that advice @PeterW I’m sure it would be 5 or 6 steps back! 

 

 

[epsilonGreedy]

On 07/01/2020 at 21:31, Russdl said:

@PeterW I was hoping you'd be there Peter ?

 

And the answer is 'B' bloody glad I asked the question! I was going to plough headlong into 'A'.

 

 

Very pleased you are asking such questions a good year before I need to know the answers. Next question is 'C' or 'D'. Should the ceiling reveal panel be fixed before the side panels? Your option 'A' diagram shows the reverse. I assume ceiling panel first is better because the side pieces then offer natural support.

[Dreadnaught]

I agree with @epsilonGreedy. I'm following this thread with great interest too.

[PeterW]

Reveals are always done top then sides - a wide reveal you may want to prop the top in a number of places until the adhesive sets. This is where dryfix foam comes into its own as you only need to prop for 15-20 mins max. 

[Cpd]

20 hours ago, PeterW said:

Also worth using decent extraction and a dust cyclone when cutting, routing or sanding Fermacell as it’s evil stuff.

Once you have used a dust Cyclone you will never look back ! I have 3, one on the router table, mitre saw and table saw and wish I had more ! Easily made my money back on not buying Hoover bags and generally destroying the motors. Rutlands do a good one but it’s not cheep. I got a cheep one of ebay and it does the job but I regret the buy as you cannot see through the plastic. 

[Russdl]

1 hour ago, epsilonGreedy said:

Your option 'A' diagram shows the reverse

 

Its doesn’t show any order. A and B are what you see as you walk in the room, either the end face of the reveals (A) or the end face of the reveals concealed by the board on the wall (B). I thought A was the way to go, fortunately @PeterW put me straight and I’m doing B. 

 

I routed a bit of the reveal last night iaw Peters's instruction and the finish seems good, the dust was immense. In places I have 5 or 10mm of overlap to route off, I think I’ll saw it off to .0001mm (roughly) before getting the router on it again.

 

Other problems I’m having...

 

Stud work not plumb, noggins not flush, hardly any of the studs at 400mm centres, and those that are at 400 centers are actually 400 and a bit which would be ok for 1220 board but not 1200 board which the Fermacell is. 

 

And a question for @PeterW if I may? If I get to a vertical board join with no stud behind it would it be sufficient to just have offcuts of Fermacell behind that vertical joint if neither board is more than 150mm from a stud? Or should I add a stud/cut the boards so the joint is on a stud?

[Dreadnaught]

14 minutes ago, Russdl said:

Stud work not plumb, noggins not flush, hardly any of the studs at 400mm centres, and those that are at 400 centers are actually 400 and a bit which would be ok for 1220 board but not 1200 board which the Fermacell is.

 

It sounds like most of your problems stem from the underlying timber frame itself being somewhat irregular, not a problem with Fermacel per se? Is that impression correct?

[Nick1c]

I thought that one of the benefits of fermacell was that sheets were butt jointed with their compound (?joint stick) and noggins weren’t needed. 

[PeterW]

22 minutes ago, Russdl said:

get to a vertical board join with no stud behind it would it be sufficient to just have offcuts of Fermacell behind that vertical joint if neither board is more than 150mm from a stud? Or should I add a stud/cut the boards so the joint is on a stud?

you can use offcuts or just put a piece of timber behind the joint and screw into that. 

[Russdl]

8 hours ago, Dreadnaught said:

It sounds like most of your problems stem from the underlying timber frame itself being somewhat irregular, not a problem with Fermacel per se? Is that impression correct?

 

I think that's a fair assessment of my problems to date, though my lack of knowledge has to share equal billing I recon.

 

8 hours ago, Nick1c said:

I thought that one of the benefits of fermacell was that sheets were butt jointed with their compound (?joint stick) and noggins weren’t needed.

 

I've found some contradictions with that, all my joints are glued with the jointstick, (when you get the hang of the applicator it works very well) and horizontal joints don't need support but it looked to me as though vertical joints did and I've endeavoured to hit a stud for each vertical joint which has been, er, challenging.

 

Thanks to @PeterW's advice I'm going to give my studs a stiff ignoring from here on in, plus I'll be using resilient bars for a fair bit of it which should make life easier.

 

I hope.

 

 

[redtop]

On 07/01/2020 at 21:16, PeterW said:

B is correct in your picture. Cut the Fermacell slightly over sized and finish with a bearing bit in a cheap router running over the face. You may need a small fine tooth saw to square off the corner. 
 

You can snap and score the reveal boards to fit with the rough edge on the inside of the routed edge, then just fill any gaps. Leave a 2mm gap from a factory edge to the frame and FST and paint the boards then finish with a bead of decent sealant between the board and the frame of the window. 

I cant find out what a bearing bit is?

[PeterW]

11 minutes ago, redtop said:

I cant find out what a bearing bit is?

one of these

 

https://www.screwfix.com/p/freud-shank-top-bearing-flush-trim-router-bit-19-x-25-4mm/2985r