Insulated plasterboard and mushrooms

whiteshadow

a plasterer was booked to do this for me but pulled out of the job.

I've got to insulate a room
I've got 13 sheets of 8x4 insulated plasterboard, 1 1/4 inch thick
I've got a box of mushroom fittings

Ive got no idea how to fix them to walls and ceiling


Can anyone give me any pointers?
thanks

bertie1

You will have to screw them to the ceiling , on the walls an adhesive mixture is normally used & then drill in the mushrooms with a masonary bit & hammer home.

northdublin

i used that type of fixing in all the rooms but i fixed the plaster board directly to the wall. they use an 8 mm masonary bit and when drilling if posible go about an inch deeper than the dept of the fixing as they tend to push dust forward of the tip of the fixing reducing the dept of the hole. i would use a good sds drill and a hoover to catch as much dust as u can as there is a lot of drilling involved. when doing it here i hit the head of the fixing untill its just below the surface of the board the i scrim taped all the heads and joints. dont worry about the dent created by the head whats important is the board is fixed propperly and doesnt move especially around the joints

whiteshadow

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

B1977

I m putting up insulated board aswell.was told to use gyproc compound adhesive.
where do you get those mushroom bolts

B1977

i am putting up plasterboard with insulation attached,any ideas how i can cut these boards to size,was also told to leave 15mm gap between floor and end of plasterboard

whiteshadow

B1977 wrote: »

I m putting up insulated board aswell.was told to use gyproc compound adhesive.
where do you get those mushroom bolts

i got the mushroom bolts in the builders providers.
just ask for mushrooms and they'll know what you mean.
thanks for tip re the adhesive

hjsimpson

The adhesive i've used is Gypsum bonding compound with pva (not ordinary bonding)
The slab is stuck to the wall wit dabs of this and secured with "mushrooms"...or insulation fixings
They are available in 50,70,90,110 mm lens (and longer) in plastic and steel.
Some plasterers dont like the steel ones....catches the trowel.
I would say u need 70 mm plastic ones and a good 8mm drill.

northdublin

B1977 wrote: »

i am putting up plasterboard with insulation attached,any ideas how i can cut these boards to size,was also told to leave 15mm gap between floor and end of plasterboard

i used a standard saw to cut them,along with a chalk line. you also need the 90 mm mushrooms and an 8mm bit if using the insulated board.and use a piece of timber to rest the board on while fixing then slide it out leaving the gap underneath.

stick-dan

Ok i work in a hardware/building suppliers so here's the heads up.

"Mushrooms"

These are actually called cavity poly fixings and come in either 80mm, 90mm or 110mm lengths. Proceed to you're local DIY and they will advice you on which to use. You say you're using insulated plasterboard known as themalboard so the odds are it is 29mm thick or 38mm thick in which case if it is the later the better fixing to go for is the 90mm or the 110mm.

To plug in these fixings you will need and SDS drill and what i believe is an 8mm SDS bit but don't quote me on the size as i'm not certain. Be sure to not buy the cheap bit. Paying that bit extra will allow you to drill easier and also make for a cleaner bore!

The bonding compound is available in all good building suppliers. A nice clean layer will suffice for good adhesion. Make sure you get bonding compound and not gypsum bonding as they serve two different purposes. Make it clear the job you are undertaking when buying.

ircoha

B1977 wrote: »

i am putting up plasterboard with insulation attached,any ideas how i can cut these boards to size,was also told to leave 15mm gap between floor and end of plasterboard

Why the gap, with the whole drive toward air-tightness?

newmills

Hi,

My mate just got the same job done to his garage walls. I could get the number of the guy that did it for him and pm it to you. He might have some more advice or he may be able to do it. Hope this helps.

John Mason

newmills wrote: »

Hi,

My mate just got the same job done to his garage walls. I could get the number of the guy that did it for him and pm it to you. He might have some more advice or he may be able to do it. Hope this helps.

hi can you pm me the details too. i have a kitchen and a bathroom that needs doing

newmills

irishbird wrote: »

hi can you pm me the details too. i have a kitchen and a bathroom that needs doing

Hi, sent it to you as required

hiscan

if your dabbing make sure you dab a full line across the top and bottom of the board if your looking for air tightness, id recommend drilling the slab directly onto the wall its a much better job plus i always use the new metal fixings its a much better job especially in the case of fire regs

B1977

ircoha wrote: »

Why the gap, with the whole drive toward air-tightness?

should i leave a 15mm gap,these boards have 50mm insulation,what would the recommended length of screw be?

championc

Hi all

I'm resurecting this old thread since I was planning to redecorate my hall, stairs and landing. I have a Semi detatched and so this is a fairly reasonable wall surface which is an outside gable end wall so reckon it's worth doing.

If I use the mushroom fixings, do I still need the bonding compound ? How many mushroom fixings do you use for each 8 x 4 sheet (maybe less fixings and more compound ) ? Is compound for attaching the boards to the wall, and if so, what are the mushrooms doing ?

Or for this gable wall, would I just be better considering external wall insulation ?


C

mad m

championc wrote: »

Hi all

I'm resurecting this old thread since I was planning to redecorate my hall, stairs and landing. I have a Semi detatched and so this is a fairly reasonable wall surface which is an outside gable end wall so reckon it's worth doing.

If I use the mushroom fixings, do I still need the bonding compound ? How many mushroom fixings do you use for each 8 x 4 sheet (maybe less fixings and more compound ) ? Is compound for attaching the boards to the wall, and if so, what are the mushrooms doing ?
Or for this gable wall, would I just be better considering external wall insulation ?


C

Its 12 mushrooms fixings to one board (Recommended)....Never used any compond to fix these to the walls.

How old is your house?

championc

1972 - so it's cavity blocks built so it's insulation on either the inside or outside of the wall


C

nophd08

mad m wrote: »

Its 12 mushrooms fixings to one board (Recommended)....Never used any compond to fix these to the walls.

How old is your house?

12 fixings per board...............Recommended by who?

smoochie06

championc wrote: »

Hi all

I'm resurecting this old thread since I was planning to redecorate my hall, stairs and landing. I have a Semi detatched and so this is a fairly reasonable wall surface which is an outside gable end wall so reckon it's worth doing.

If I use the mushroom fixings, do I still need the bonding compound ? How many mushroom fixings do you use for each 8 x 4 sheet (maybe less fixings and more compound ) ? Is compound for attaching the boards to the wall, and if so, what are the mushrooms doing ?

Or for this gable wall, would I just be better considering external wall insulation ?


C

http://www.xtratherm.com/wallsolutions/wallindex.php

This is the website i used for my DIY job. I used 8 mushroom fixings. Two of these need to be galvanised steel for fire regulations iirc. I didnt use compound i just fixed them directly to the wall with the mushrooms.

That link gives you a short video of what you need to do and i found it very helpful. Hope it helps you.

CBYR1983

I had a hall stairs and landing done a few weeks ago. Also did gable end of box room.

Make sure you have enough depth if the staircase runs along the wall. I put a thin half d-shaped piece of architrave along the string of the wall, roughly 40mm depth, maybe 12mm thick. Otherwise the boards would have protruded nastily over the wall string, which was only giving me about 20mm from the wall.

Then I used 38mm warmboards. It looks neat.

There's a window on the gable wall of my house as well, thankfully the windowboard had ample depth and the reveals were plastered.

Loads of dust from the drilling though - be prepared.

Well worth doing though. Have a think about other walls while you're at it, even though it's awkward to take off rads and that at this time of year. I bought the stuff from "U-Value".

bobbuilder

Hi im a plasterer by trade warm boards are stuck to walls or they are fixed not stuck and then fixed your wasting money and time doing that

championc

CBYR1983 wrote: »

I had a hall stairs and landing done a few weeks ago. Also did gable end of box room.

Make sure you have enough depth if the staircase runs along the wall. I put a thin half d-shaped piece of architrave along the string of the wall, roughly 40mm depth, maybe 12mm thick. Otherwise the boards would have protruded nastily over the wall string, which was only giving me about 20mm from the wall.

Then I used 38mm warmboards. It looks neat.

There's a window on the gable wall of my house as well, thankfully the windowboard had ample depth and the reveals were plastered.

Loads of dust from the drilling though - be prepared.

Well worth doing though. Have a think about other walls while you're at it, even though it's awkward to take off rads and that at this time of year. I bought the stuff from "U-Value".

Sounds like it was good timing on your part given the recent weather. Probably too early to tell the effectiveness - yes ?

paddy147

CBYR1983 wrote: »

I had a hall stairs and landing done a few weeks ago. Also did gable end of box room.

Make sure you have enough depth if the staircase runs along the wall. I put a thin half d-shaped piece of architrave along the string of the wall, roughly 40mm depth, maybe 12mm thick. Otherwise the boards would have protruded nastily over the wall string, which was only giving me about 20mm from the wall.

Then I used 38mm warmboards. It looks neat.

There's a window on the gable wall of my house as well, thankfully the windowboard had ample depth and the reveals were plastered.

Loads of dust from the drilling though - be prepared.

Well worth doing though. Have a think about other walls while you're at it, even though it's awkward to take off rads and that at this time of year. I bought the stuff from "U-Value".

Or you could just remove your entire staircase and landing and insulate completely.

What the hell was I thinking,at the time.:D

Buford T Justice

If a job's worth doing though..........

CBYR1983

paddy147 wrote: »

Or you could just remove your entire staircase and landing and insulate completely.

What the hell was I thinking,at the time.:D

Wow- that's some job you took on there! We're living in the house with a small child so that type of destruction wasn't an option - but i imagine your effectiveness is way higher. We did under the stairs too but obviously missed those spaces. What thickness did you use? Some job, fair play.

In fairness we do seem to be noticing the difference - the hall used to be an ice box and we even had condensation forming mould on the gable wall. Place was much cosier during the recent cold snap - happy to have done it, even if there was some hassle and inevitable redecoration. I like the idea of keeping the heat in rather than heating the walls. We're not there during the day, and external retro-fitted seems too messy, risky and awkward to me.

championc

I too don't particularly want to heat my walls. Does anyone know if 4" of outside insulation the same as 4" inside or would the equivalent be less ? I cannot really see myself installing more than about 40mm on the inside - and that would include the plasterboard too.

CBYR1983

Pics

handlemaster

CBYR1983 wrote: »

I had a hall stairs and landing done a few weeks ago. Also did gable end of box room.

Make sure you have enough depth if the staircase runs along the wall. I put a thin half d-shaped piece of architrave along the string of the wall, roughly 40mm depth, maybe 12mm thick. Otherwise the boards would have protruded nastily over the wall string, which was only giving me about 20mm from the wall.

Then I used 38mm warmboards. It looks neat.

There's a window on the gable wall of my house as well, thankfully the windowboard had ample depth and the reveals were plastered.

Loads of dust from the drilling though - be prepared.

Well worth doing though. Have a think about other walls while you're at it, even though it's awkward to take off rads and that at this time of year. I bought the stuff from "U-Value".

how wide was your stairs. mine is only 820. Purchased 38mm which would bring it below the 800 allowable

CBYR1983

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.