Insulating attic room - wood fibre boards

[Aofan Winsey]

Hello,

I moved into my house last year and have been gradually improving things, the last room which needs attention is the attic room. It is part of the original house (c.1770 I think) and has always been a room. I want to insulate the room with wood fibre boards so it is useable (its freezing in the winter and roasting in the summer) and block up the gaps in floorboards and skirting boards with wood slivers (or something else, just not expanding foam). I think the paper probably needs to be stripped but I'm really not sure and was hoping someone would have advice on how to approach the work.

I have asked around 6 local handymen/builders to quote for the work but none seem interested even to have a look. I'd love to pay someone to do it properly but if I understood what needed to be done I would probably do it myself.

Any advice much appreciated!

 

[Cubist]

Well... that's a bloody orrible pink and it desperately needs either to be banished into history with more paint or better yet thoroughly stripped off those walls and ceilings...and anywhere else you find it. Theres an equally desperate need for the dog to be able to see the rabbit in this room. From the little that can be seen the house, certainly in this part of the structure, is a heavy timber frame under a slate roof. The second photo also suggests that the slates, if that's what can be seen, are almost in direct contact with the whatever has been used to form the ceilings. On balance I would suggest that someone has lined the bulk of that space with plasterboard before slapping on some lining paper and said orrible paint.

If you ever got a tradesperson to look at the room he/she would probably have run away screaming, not from the colour, but because there is no way a reasonable quote could be arrived at before all that plasterboard, paper and paint has been removed to reveal.... well that's the $64,000 question. What does all that stuff hide?

Before going any further do you have any DIY competence? And would you be aware of the risks associated with removing all that material safely?

 

[Aofan Winsey]

Thanks for the response, I know the pink needs to go. My DIY competence may not extend to whatever lies beneath this which is why I wanted to pay someone more competent but after weeks of getting nowhere with that I am considering other routes. I suspect these photos have put off any potential builder from wanting to touch it for the reasons you mentioned.

My main question is do I need to strip everything off the walls and ceiling or can I just add wood fibre insultation ontop, get it skimmed and paint it? Obviously its not ideal and it would be a much better job if this was done but what are the potential issues if boards were just added ontop?

If I did strip off the paper and plasterboard what kind of prep would I potentially have to think about before adding the wood fibre boards?

Thanks again.

 

[Kearn]

Depends on what you have frankly. Looks like plasterboard with lining paper. What depth are your commons? What’s the external makeup above the commons? Torching if you do indeed have slates? How deep are the batons?

Without knowing too much, I’d be using wood fibre batts between the commons, not full depth so you have some air gap above the fibre below the tiles. Then underneath, depending on depth of wood fibre achieved, I’d use wood wool or wood fibre boards attached to the commons, then lime plastered.

All in, you want at least 100mm of insulation, more if feasible. However, wood wool boards are much easier to plaster onto than wood fibre, but don’t have the insulation properties.

If you’re lucky enough to have full lime render under the tiles instead of torching, then you can forego the air gap and push wood fibre batts up to it.

If you have lime plaster on lath, that’s a different story.

First things, investigate what’s there and understand what you have to play with.

 

[Cubist]

The major worries I would have are mostly associated with damp induced by water penetration from around the roof, or through condensation out of warm air above and behind the plasterboard. It's unlikely to have been significant in the past as evidence would have become obvious inside the room? Damp timbers can attract woodworm and only by exposing the timbers to allow them to be treated and thoroughly dry out would that problem be avoided in the future. Of course any timbers that have been significantly worm damaged may need surgery. Electrics for lighting and portable and semi-portable kit will have been installed at some time and care needs to be taken when removing the plasterboard to ensure that you do not inadvertently cut or nick a wire. The wiring may be quite old and you would need to consider replacing it and perhaps all the way back to the consumer uint. Presumably some form of heating was used in that space. If a wet CH system then the pipes probably run under the floor boards to emerge somewhere on the surface again care needs to be exercised not to damage the pipes - many modern systems use small diameter (10mm) pipes and these can be delicate. Particular care needs to be taken if moving them or using hard tools anywhere near them.

On the plus side the plasterboard will have been fixed to a wooden timber frame, some of which will probably have been attached to the main trusses beams and other events of the roof structure. This may, if its in good condition and of sufficient dimensional strength provide a ready base of the new insulating materials you are thinking of - best to seek advice from others here on that topic when the time comes. That said don't be tempted to swing a hammer at the plasterboard until you know how far away from the outer wall the inner surface sits. It's best to simply cut a small section out to allow closer inspection before you get heavy handed. The lining paper and paint will simply come out with the waste board so I wouldn't fuss with that except where the main timbers of the roof have perhaps been painted in the past. Ideally you will need to get rid of that too as it may be a plastic based paint that limits the woods ability to breathe. Oh, and make sure you use appropriate masks when shifting those painted boards - it could be lead paint and small people and animals will need to be kept out.

 

[Aofan Winsey]

Thanks again both for your advice.

Over the weekend I cut out a section of the boarding on the slanted bit of wall beside the window and I think its good news. The boarding is thankfully not plasterboard but 15mm thick board (like compressed paper?), its very easy to cut and not particularly dust generating in any case which is a relief. It revealed the roof felting behind with a small air gap. See photos. I also attached a photo showing the other end of the room with the working light and radiator, I think most of the work was done in early 2000s so probably isn't old enough for lead paint. The light fixture on the ceiling and light switch are defunct but I would get my electrician to properly check and decommission it all.

So would this mean I could just remove all the existing boarding and directly attach wood fibre boards to the existing wooden timber frame? Should I leave the small air gap (about 20/30mm) or stuff it with insultation? Would I need an air tightness membrane (in front or behind the wood fibre boards)? I was thinking of using 40 or 50mm wood fibre boards which I realise is much less than the 100mm min recommended but that thickness would restrict the useability of the room.

 

[a twig]

So you have some sort of insulated board / wood fibre there already by the looks of it and you’re now cutting it out to fit wood fibre board?

Sorry I’m a bit lost

 

[almostatmywitsend]

Is your property listed?

 

[Aofan Winsey]

I had no idea what I had until I cut into it yesterday but whatever that stuff is it is doing absolutely nothing to insulate the room. Its also been really shoddily installed (like everything else in house), bad jointing, poor finish etc. If its possible to just add wood fibre boards ontop of the existing boarding that would be ideal as its less to do but I assume that's not advised for the reasons Cubist mentioned re. damp.

 

[Cubist]

Could be that I simply assumed it was plasterboard but maybe that conclusion didn't make an ass of me on this occasion. That last photo suggests a circa 20mm - or even less? - thickness of a fibre board of some kind. How well that board may perform in terms of thermal or acoustic insulation will be open to conjecture but, if the black material to the left in that last picture is the underside of the roofing felt then the inner face of the board is, to my limited knowledge, too close to permit effective airflow and therefore could be/become a source of trapped condensation. There are others here who have more direct experience than I who may be able to comment/advise but I would suggest that @Aofan Winsey needs to research the topic more thoroughly before making any final decisions - about anything other than that paint.

 

[Kearn]

We had some wonderful early attempt at eco something or other, maybe, or maybe not… 3” of a compressed straw board, wrapped in paper. Attic was full of it… while it may sound like the same stuff I popped back in, it certainly wasn’t insulating, good knows what else it contained and mine was not clean and easy to get out! Think it was lined with lead….!

Your roofing felt is probably beyond its last legs, it’s sagging almost further into the room the underside of the rafters and I can’t figure where the battens come into play …therefore close to zero air gap, and no chance of squeezing some woodfibre or sheepswool between them before boarding under.

If you’re going to do a roof, do it right and do it once. Might be that you need tiles off and to sort airflow and the rest while you’re up there.