Insulated plasterboard and mushrooms

handlemaster

CBYR1983 wrote: »

Is that wall to wall? I have well over 800 when I take in above the banister. I never had that just on the treads.

From the inside of the handle rail to the wall is 820 if the hand rail was taken off the out side the support there would be 850

CBYR1983

If you need to get a wheelchair up it fully open then I'd worry, otherwise for the vast majority the cold is more of an issue imho.

Unless you're planning on adding a stairmaster!

Sounds like your rail is screwed to the opposite wall? My is open on opposite side to gable, but with banister.

Grove85

I just did this job in my own house.
I got 50mm boards. Fixed them with 110mm mushrooms. Using an 8mm sds bit. Put a piece of electrical tape on the bit, a wee bit deeper than the depth of the mushroom. You don't want to go all the way into the cavity. Don't whack in the mushrooms all the way till you have most in. Then sink them just under the surface. Use about 9 for a 8x 4 sheet. Then consider using a filler and jointing tape over the mushrooms when filler still wet. Damping the tape a bit. The mushrooms can appear through paint if just skimmed over. I'm not a professional but this was my approach.

Geezy

Does anyone know how to remove these steel mushroom fittings? Presuming I need to drill them out with a metal bit?

ballystephen

Dot n Dabbed mine about 10 years ago . Still grand

EugenesDIYDen

I've seen some posts elsewhere from people that had staining problems on paint.
Has anyone come across this very often?
One theory is that it's due to thermal bridging when mushroom fixings are used and moisture condenses on the surface of plaster directly over the heads. The other theory is that paint soaking into the skim reacts with the metal of the fixings, creating an oxide/rust that then leaches to the surface. A plasterer advised me to prime the heads to stop this and use plastic caps to cover the heads.
Is there any sort of insulating filler that could be used to cover the depression over a mushroom head that would eliminate condensation?

listermint

EugenesDIYDen wrote: »

I've seen some posts elsewhere from people that had staining problems on paint.
Has anyone come across this very often?
One theory is that it's due to thermal bridging when mushroom fixings are used and moisture condenses on the surface of plaster directly over the heads. The other theory is that paint soaking into the skim reacts with the metal of the fixings, creating an oxide/rust that then leaches to the surface. A plasterer advised me to prime the heads to stop this and use plastic caps to cover the heads.
Is there any sort of insulating filler that could be used to cover the depression over a mushroom head that would eliminate condensation?

Advice with mushrooms is to spray them with antioxide paint prior to plastering.

dodzy

listermint wrote: »

Advice with mushrooms is to spray them with antioxide paint prior to plastering.

Just don't use the metal fixings. Go with the plastic variants.

bman1

I work in a hardware shop and all our current suppliers changed to metal a few years ago, can't get plastic now. That's not to say other suppliers aren't still doing them. We've been told by a good few tradesmen now that they use B.I.N primer for priming the heads of the fixings, and it's available in a spray can so they prefer that to going at each fixing with a paint brush. Now none of that is gospel but these fellas are at it years and tend to learn what works and doesn't work I suppose.

EugenesDIYDen

bman1 wrote: »

I work in a hardware shop and all our current suppliers changed to metal a few years ago, can't get plastic now. That's not to say other suppliers aren't still doing them. We've been told by a good few tradesmen now that they use B.I.N primer for priming the heads of the fixings, and it's available in a spray can so they prefer that to going at each fixing with a paint brush. Now none of that is gospel but these fellas are at it years and tend to learn what works and doesn't work I suppose.

What's B.I.N. and would red oxide primer work?
Is this staining thing really a common issue with plasterboard if there is good ventilation and no activities in a room that generate moisture such as drying clothes on radiators and cooking? The room is a kitchen, but unlike years ago there's no boiling on the cooker, mostly microwaving and short duration use of the oven. What do I fill over the mushroom heads with and could I use a non-expanding foam?

dodzy

EugenesDIYDen wrote: »

What's B.I.N. and would red oxide primer work?
Is this staining thing really a common issue with plasterboard if there is good ventilation and no activities in a room that generate moisture such as drying clothes on radiators and cooking? The room is a kitchen, but unlike years ago there's no boiling on the cooker, mostly microwaving and short duration use of the oven. What do I fill over the mushroom heads with and could I use a non-expanding foam?

this is B.I.N

https://www.woodies.ie/zinsser-500ml-bin-primer-seal-1112573?utm_source=google_shopping&gclid=EAIaIQobChMIiqSTq7TB1wIV7b_tCh0ZiApZEAQYASABEgKunvD_BwE

And the mushroom fixtures are flat headed and hammered home (into predrilled holes) fractionally below the plasterboard surface and then plastered over.

EugenesDIYDen

dodzy wrote: »

this is B.I.N



And the mushroom fixtures are flat headed and hammered home (into predrilled holes) fractionally below the plasterboard surface and then plastered over.

Is the idea of this stuff to prevent any staining from mildew or to stop any reaction products from emulsion paint and the metal head of the mushrooms leaching out through the plaster?

1983ish

I filled the metal fixings with normal silicone then put the caps on. Bout 2 years ago and no issues so far

EugenesDIYDen

1983ish wrote: »

I filled the metal fixings with normal silicone then put the caps on. Bout 2 years ago and no issues so far

Do the caps bring the heads above the surface? I'm barely recessing them and not going to skim. Didn't skim attic room plasterboard 25 years ago, just painted and still fine.

1983ish

Caps are only 2/3mm thick
Id say you’d have to sink them a bit then fill over the caps/fixings if your not plastering

EugenesDIYDen

1983ish wrote: »

Caps are only 2/3mm thick
Id say you’d have to sink them a bit then fill over the caps/fixings if your not plastering

Might be a little difficult without tearing the paper. It's the edges that are hard to recess without doing damage. I'm using a short piece of brush handle as a punch which works well. It's easy to go around the perimeter of the head and hammer down.

randombar

Re-Resurrecting an old one here.

Have a cavity block garage and had the insulation board for about 2 years for it. Do people recommend dabbing or mushrooming?

Also required tools? Apart from SDS drill and decent 8mm bit. Put a few ceiling board up yesterday. Discovered I need a tool belt to hold all the damn screws and hook the drill onto Guessing chalk line.

EugenesDIYDen

GaryCocs wrote: »

Re-Resurrecting an old one here.

Have a cavity block garage and had the insulation board for about 2 years for it. Do people recommend dabbing or mushrooming?

Also required tools? Apart from SDS drill and decent 8mm bit. Put a few ceiling board up yesterday. Discovered I need a tool belt to hold all the damn screws and hook the drill onto Guessing chalk line.

I finished insulating my kitchen last year. After hammering the mushrooms flat onto the board I used a short piece of brush handle (a few inches long) to recess the heads, painted over with red oxide and filled. Haven't had any issues with dark patches after giving the room two coats of Dulux kitchen paint.
Is your board bowed after being in storage? Bring it somewhere warm to let it dry out if that's the case. Mine was a bit bowed which caused issues then when I installed kitchen units (walls were probably not level/plumbed in any case).
As regards tools, unless you have a helper, you'll need something to prop against the boards while installing if you're using mushrooms until you get a few in. I used some shims of timber underneath to push the boards tight up against the ceiling, but that was really so that there were no gaps. If you have a 4 stone weight or something else heavy, you can prop a timber board against it and against the sheet to keep it in place. The 65mm stuff weighs about 30kg and is awkward and fragile.

EugenesDIYDen

Here's some images before a moderator removes them:
https://www.facebook.com/groups/203863340138801/permalink/295499120975222/

randombar

EugenesDIYDen wrote: »

I finished insulating my kitchen last year. After hammering the mushrooms flat onto the board I used a short piece of brush handle (a few inches long) to recess the heads, painted over with red oxide and filled. Haven't had any issues with dark patches after giving the room two coats of Dulux kitchen paint.

Did you skim after or paint?

EugenesDIYDen

GaryCocs wrote: »

Did you skim after or paint?

No, just painted. Those washable kitchen emulsions are quite thick and cover everything. Plastering on the joints turned out fine too. You cant see where the joints are unless a torch is shone sideways along the walls.

EugenesDIYDen

Dabbing is probably quicker and cheaper, but what I was worried about was if I didn't get all the dabs the same height, the boards wouldn't sit flat on the walls. I don't know either whether it's possible to re-align boards once they're pushed tight onto the dabs.

EugenesDIYDen

When you get to the painting stage, thin the first coat with 10% water so that it penetrates in and binds. Alternatively use the PVA stuff. I just thinned. Paint hasn't peeled off yet and it's done nearly a year!

sheff the ref

Has anyone used these type of twist fixings

Are there less of these needed than standard mushroom fixings as they are considerably more expensive

listermint

Use spray foam plaster board fixing. I've used it everywhere in the house bar ceilings. You'd have to be seven shades of stupid to get it wrong. It also provides a thermal break.

Cerco

whiteshadow wrote: »

hi what sort of adhesive mixture ? and what sort of screws would i use?

listermint wrote: »

Use spray foam plaster board fixing. I've used it everywhere in the house bar ceilings. You'd have to be seven shades of stupid to get it wrong. It also provides a thermal break.

Did you use mushroom fixings as well? Which foam would you recommend?

listermint

Cerco wrote: »

Did you use mushroom fixings as well?

No not at all. Why would I double up ? The foam sets like concrete.

the_pen_turner

listermint wrote: »

No not at all. Why would I double up ? The foam sets like concrete.

fire regs

10-10-20

I used Pink Grip when fitting insulated boards. Other expanding foam wasn't as good at all. It's pricey and I found that when it said that I'd get 5 boards to an can - it was all lies and I only got about 2 boards to a can. I had a fair few cuts to make in fairness. The builders-providers might do a deal on multiples.
In terms of simplicity, it is easy enough, but you do have to baby-sit the freshly applied boards for at least 20 mins afterwards as they can expand after application (even with 4 and a half mins of expansion time before application of the board to the wall).
And yes, you are supposed to support the boards with mushroom fittings as a second level of support. I realised that when one of the boards delaminated on a small patch of wall which I hadn't treated for dust (using SBR).

Calahonda52

listermint wrote: »

No not at all. Why would I double up ? The foam sets like concrete.

fire regs require a certain % of metal mushroom fixings per sim