Masterboard under hearth when installing stove?

[squarelips]

Hi all,

 

I am trying to instal a stove on my grp boat and i aint never done this before so asking lots of questions of you wonderful boaters to try to keep me right.

 

following these guidelines:

http://www.soliftec.com/Boat%20Stoves%201-page.pdf

 

1 It is saying the surrounds should be made of 25mm masterboard but thats SO expensive. And at a boatyard they said 12mm would do it. Who should i trust?

 

2 and for the hearth under my stove. i'm worried that the master board will be really brittle under a heavy stove with the 10mm air gap? Is it cool to just put lots off cuts under to keep it sturdy?

 

3 my stove is on long legs maybe 20cm. do you think under the hearth that will allow me to use less master board under the cement board??

 

4 - how would you suggest that i fix my stove firmly in place??? it must be important because they've written it in bold!

 

Thank you for any help you can give me. Sorry if these questions seem really simple but i've never done this before. So thanks for your patience.

[Murflynn]

I cut the floor out under the stove and cast a concrete plinth off the baseplate, with holes left in for setting in holding down bolts (set in epoxy mortar) for the legs of the stove.

 

I laid quarry tiles under the stove and around the legs.

 

I used 12mm aquapanel for the surround, fixed to timber battens with a 2" air gap behind, then tiled. You should follow the recommendations for the air space between the stove and the surroundings.

[squarelips]

thanks murflynn - do you think because my stove is on legs it'd be safe not to put down master board? just 18mm ply and then cement board?

under the ply there is another big air gap of about twenty cm down to the hull.

 

thanks man

un

[Dave Payne]

I put 25mm fireboard under the slate which my stove sits on, cost about £30/sheet and one sheet needed so not that expensive.

 

End game, the wood that's under the fireboard remains cool.

 

Worth every penny in my opinion.

[Murflynn]

thanks murflynn - do you think because my stove is on legs it'd be safe not to put down master board? just 18mm ply and then cement board?

 

haven't got a clue.

 

I am (was) a civil engineer which is why I believe in robust engineered solutions.

[J R ALSOP]

I would moor near a bridge so that the Fire service has easy access, In my opinion plastic boats and solid fuel stoves do not go together. I have done many disposals because of such fires.

[WotEver]

I would moor near a bridge so that the Fire service has easy access, In my opinion plastic boats and solid fuel stoves do not go together. I have done many disposals because of such fires.

About as helpful as...

 

if you have to ask a question like that you should not be on a boat.

Edited December 2, 2016 by WotEver

[squarelips]

hey you lot - thanks for all your help and advice. still trying to figure all this out.

thanks for your warnings too J R ALSOP it defo is hammering home the importance of doing this safe and correct but I have seen lots of grp boats with stoves and am confident i can do this safely.

 

and dave payne where did you get fireboard for 30quid? im looking at masterboard from travis perkins

 

here https://www.travisperkins.co.uk/Product/Building-Materials/Insulation+Plasterboard/Plaster+Plasterboards/Fire-Resistant-Boards/c/1500012

 

and 12mm is like 140quid. I cant even find 25mm masterboard.

I am willing to spend the money if its going to make sure my boat doesn't melt! ha ha

 

I still really cant think of a solution for how to fix my stove firmly in place.

 

thanks for all your help.

[blackrose]

I used 6mm masterboard and it's fine without any air gaps. I followed the stove manufacturers guidelines re. distance from stove to combustible materials. Mine is a big 9kW stove sitting on a big hearth and its completely lined, even behind the flue.

 

In terms of air gaps behind the master board, if you batten out an air gap with wood then you're back to square one and wasting your time. You'd have to do it with an incombustible material like offcuts of tile stuck together with high temp silicone, but even that might conduct the heat and scorch something behind that you can't see.

 

I used slate effect tile over the masterboard on the floor. It doesn't really get hot underneath because heat rises, but the slate does get warm where the stove throws out the heat in front. On the walls I used sheets of copper-effect anodised aluminum instead of tiles. It seems to reflect the heat back out.

Edited December 3, 2016 by blackrose

[squarelips]

amazing black rose! thanks for that advise. I was totally going to use wood offcuts to create the air gap. I'm really glad you pointed that out to me! I think im gonna get the 12mm masterboard and be done with it.

 

That was really helpful of you. thank you x

[blackrose]

amazing black rose! thanks for that advise. I was totally going to use wood offcuts to create the air gap. I'm really glad you pointed that out to me! I think im gonna get the 12mm masterboard and be done with it.

 

That was really helpful of you. thank you x

Just try to increase the gap between the stove and any wood or combustible materials around it, as well as between the stove and your masterboard/tiles.

 

Someone may have already mentioned this but you can use Plumbaflu or other high temp silicone to stick masterboard down rather than using screws which conduct heat. But make sure you get it right first time because you'll wreck the masterboard if you need to get it up again. Use high temp silicone to stick tiles on the master board too. Just use a blob in each corner and perhaps one in the middle of each tile. It tends to be much more flexible than tile adhesive. Then just grout with a flexible grout.

Edited December 3, 2016 by blackrose

[squarelips]

thanks blackrose - really helpful! I'm slowly but surely getting there and learning a lot along the way. I found these guys

 

https://www.thestonebakeovencompany.co.uk/shop/additional-insulation-materials/2-x-25mm-calcium-silicate-board/

 

selling really cheap 25mm calcium silicate but i gots a feeling the boards will be really small cos they dont mention size at all. so i might even be able to upgrade to 25mm masterboard!

I cant wait to get this stove in and heating up ma little boat!

 

Thanks for taking the time to help me out. Very very appreciated x

[Dave Payne]

Got mine off eBay, but looking now they don't seem to have any listed at the minute.

[nbfiresprite]

I got my from Midland Chanders on ebay, which worked out cheaper then the website due to the 20% discount on ordering two or more.

 

Sheet size 1000x600x25

 

http://www.ebay.co.uk/itm/Fire-Brick-Heat-Protection-Board-Narrowboat-Home-Stove-/281907454524?hash=item41a2fe623c:g:Sb4AAMXQwwlSC3-W

[blackrose]

thanks blackrose - really helpful! I'm slowly but surely getting there and learning a lot along the way. I found these guys

 

https://www.thestonebakeovencompany.co.uk/shop/additional-insulation-materials/2-x-25mm-calcium-silicate-board/

 

selling really cheap 25mm calcium silicate but i gots a feeling the boards will be really small cos they dont mention size at all. so i might even be able to upgrade to 25mm masterboard!

I cant wait to get this stove in and heating up ma little boat!

 

Thanks for taking the time to help me out. Very very appreciated x

I've never seen the 25mm thick stuff. If it's really heavy and you're using high temp silicone to stick it to the wall you might need to use a bit more. (It's probably full of air and not that heavy.)

 

By the way, I know that B&Q do a big sheet (8x4) of heat resistant board for about 12 quid. However I'm not sure if it's the right stuff for hearths? I think probably not?

 

http://www.diy.com/departments/gyproc-fireline-square-edge-plasterboard-l2400mm-w1200mm-t125mm/35764_BQ.prd

Edited December 4, 2016 by blackrose

[Jrtm]

I use and so do others with wooden boats use cement partical board (cpb) b&q sell it its arout 10-20 a sheet its around 8mm thick you dont want cement fiber board (cfb) its not as strong you can tell if your looking at the right stuff as if you put your finger on a corner if with some but not much effort it brakes its fcb if you put lots of pressure and it either brakes or dosnt its cpb.

 

If you can put an air gap between the pcb and stove but you can bolt strait to it but not advised.

Ill try to find the link

 

http://www.diy.com/search?Ntt=cement+board

 

We use to use 4-6mm for the base plate ontop of the plinth was going to use the same but found this stuff at b&q

 

anyways avoit the fiber board its just to brittle.

Edited December 4, 2016 by billybobbooth

[Jrtm]

Forgot to add you need a jigsaw to cut it its very hard to cut threw. But you xan tile onto it if you wanted to.

Edited December 4, 2016 by billybobbooth

[Murflynn]

 

By the way, I know that B&Q do a big sheet (8x4) of heat resistant board for about 12 quid. However I'm not sure if it's the right stuff for hearths? I think probably not?

 

http://www.diy.com/departments/gyproc-fireline-square-edge-plasterboard-l2400mm-w1200mm-t125mm/35764_BQ.prd

that is plasterboard.

 

Aquapanel is a cement board on a matrix of something like glass fibre, is widely available and very strong. Try Wickes.