Kitchen roof and ceiling

[Mish]

Hello kindly folk

Would love some advice. I live in a mid-terrace cottage, probably around 200 years old, not listed. We've been aware for a while that water has been getting into the kitchen ceiling, but now there are some major leaks.

It's a small kitchen at the rear of the cottage, single storey with single pitch roof, probably a former scullery or outbuilding. We've now removed the stained and warped old hardboard ceiling that followed the line of the roof, and this has revealed hardwood rafters. I understand the cottage used to be thatched, and a room like this would most likely have had no ceiling anyway (the painted rafters also backs this up).

Although we need to address the gaps in the roof tiles first of all, I'd really like some advice on the ceiling. Should it be reinstated or left open? If it's reinstated it would need to be sloping and follow the line of the roof. Should we go for lath and plaster? Perhaps matchboarding? If it's left open, I presume we'd need to put something between the rafters so that the roof tiles aren't exposed? Some insulation would be sensible as it gets quite chilly in the kitchen and we don't have central heating. I like the sound of sheep's wool.

Photos to follow within the next hour.

Looking forward to hearing your thoughts.

 

[Zebra]

How deep are the rafters? Any kind of insulation needs a decent depth to be effective. With roofs you also have to consider ventilation so that moisture doens't get trapped in with your rafters and cause mould and rot. With most types of insulation you need to leave a 50mm gap above the insulation, below the tiles or membrane. Is there a membrane under the tiles in the roof or can you see the tiles from below? If there's a membrane, I presume it's not one of the new breathable kind but is black roofing felt?
What the ceiling is made of doesn't matter too much as I understand it. You could use plasterboard and modern plaster, woodwool board and a lime plaster, or laths if you want to go the whole hog. You could put the ceiling below the rafters, or in between them, leaving them exposed.
But exposing the rafters will most likely cut down on the depth of insulation you could use. In my upstairs room the rafters are 75mm deep, so I've inserted 50mm of a rigid foam insulation (as this is the most effective type for a given thickness) with a 25mm airgap above. As the roof is so well ventilated at the eaves I've compromised on the air gap. I've deciced not to leave the rafters exposed because to do so would cut down so much on the amount of insulation I could use.
Underneath the rafters I'm thinking of using one of the multifoil products, because even though they are controversial, they can be quite effective if you have a limited space.
I've used sheepswool in the walls, but not in the ceiling because of the limited space. Sheepswool is less thermally effective than a rigid foam insulation, but of course it is breathable. It depends whether this is important in your situation. I found Thermafleece to be very helpful, and they would calculate the thermal effectiveness of your proposed system for you if you phone them up.
There are also other breathable insulation types, such as woodfibre (brand names Gutex, Diffutherm, Homatherm, Steico).
You may need to consider using a vapour control layer on the inside of the insulation to prevent moisture from reaching the rafters and settling there. As opposed to a vapour barrier which is polythene, some types of vapour control layer will let some moisture through.
Sorry this is rambling. I'm no expert, I've just done a lot of research myself. But normally on here I'm asking the questions, not giving the advice. Hopefully there are others on here who will give you a clearer answer!

 

[Mish]

Hi Zebra, thanks so much, all really interesting and useful. At the moment the underneath of the tiles have what I think is bitumen stuck to them. We haven't tackled the kitchen at all yet, as you will see.

 

[Penners]

I agree with pretty well everything that Zebra has said.

From your description, I'm assuming that this kitchen is a lean-to structure on the back of the house, with two or even three external walls. So it's pretty well bound to have considerable heat-loss problems. That being the case, if it were my house (and if the wall height permits it), I would insert a suspended, level ceiling. This would consist of softwood joists above a 12mm plasterboard ceiling. Above the ceiling I would pack in a hefty thickness of insulation - if you use a conventional rockwool or plastic-bottle-wool then you need at least 230mm thickness.

This would leave you with what is termed a "cold roof". Given your problems of leaks (and, I assume, no membrane) I would strip the roof and relay it properly with a breathable damp-proof membrane underneath (such as Tyvek - there are many others).

As this is a kitchen, I would fit the room with an extractor fan (minimum rating around 230 m^3/hr for an average kitchen) controlled by a humidistat.

 

[Mish]

Hi Penners, thanks for your thoughts. Sorry, delay with my posts appearing as they're being approved by a moderator before going live. There are now some photos of the kitchen appearing before your reply. Interesting ideas about a suspended level ceiling, but not possible in this case because the roof level starts at 5'8", and although it goes up to 9', the room is small (7''7" x 7'3"). Before we removed the hardboard ceiling and fibreglass insulation, it didn't get particularly cold in the kitchen. It is indeed a lean-to structure on the back of the house, but with only one external wall. Our our neighbour is on another side, and our bathroom is on the third side.

Zebra, I've now measured the rafters and they're around 80mm to 100mm deep.

 

[Penners]

the roof level starts at 5'8"

In that case you could consider a ceiling that follows the rafter line up to a comfortable height (perhaps 7ft to 7ft 6in) and then insert horizontal joists for a suspended ceiling. In view of the low rafter height at the eaves you probably won't want to add spacers to the bottom face of the rafters, to give you more insulation space between them, but if you use foam insulation batts between rafters this will maximise the insulation that can be achieved in that area of the ceiling. Then, when the ceiling levels off, you can pack in the rockwool (or whatever you choose).

 

[Mish]

Thanks Penners. Meant to mention that because the kitchen is so small, we can't afford to lose any of the wall space where the shelves and cupboards will be placed. So in this instance we'd like to go with a ceiling that follows the line of the roof, but at least that's one less decision to make. Thanks for your thoughts on the insulation batts - will look into that.

Also interested to know if anyone here can share examples of how they've made the most of a small kitchen.

 

[Feltwell]

9' is pretty high though Mish - though I personally do like the look of that. The "flattened" celing arrangement, for want of better description, is what has happened in our scullery. The original lath & plaster ceiling was attached directly to the bottom of the rafters, going from a wall height of around 6' on one side of the room to around 11' on the other. A previous owner put ceiling joists in horizontally part way up as Penners describes, then plasterboarded over. I've cut a loft hatch in and added lots of rockwool insulaton in the flat section, and I added some kingspan insulation to the sloping part between the rafters when we replaced the roof tiles - we'll probably underclad with some insulated plasterboard on the sloping part at some point, as currently the thickness of insulation isn't great.

The "new" ceiling arrangement undoubedly helps keep the room warmer as it both reduces the volume of the room in a critical area and provides lots of room for insulation (cheap insulation at that) as well as providing a very useful void for cables etc. Aesthetically it looks OK but I can't help that feel that the original arrangement would look better - in which case I would have inserted some kingspan/celotex in between the rafters (leaving an air gap under the roofing membrane and tiles) and then underclad with insulated plasterboard. I'm not sufficiently bothered to change it however!

Picture below to help you decide on the aethetics - please ignore all the junk, it's now the kids playroom, the TV being permanently hooked up to a Wii, and yes it needs decorating! Must get around to fitting that bit of trunking I bought to hide the cables as well.......

Edit - just spotted a misplaced apostrophe, better get in there before the punctuation police arrive!

 

[Penners]

because the kitchen is so small, we can't afford to lose any of the wall space where the shelves and cupboards . Also interested to know if anyone here can share examples of how they've made the most of a small kitchen.

OK, understood. Our kitchen is small - about 7ft 6 x 10ft - and it's set out galley-style. I can't take a photo right now, because the Managing Director is cooking a family Sunday lunch.

Me: "Could you just go out of the kitchen for a few minutes while I take a photo?"

MD: " Of course I can. I can see that your photo is much more important than an oven full of BURNED FOOD!!"

I'll try and remember to take a shot later or tomorrow, and post it.

 

[Mish]

Hi Feltwell, thanks for the ideas and the photo - very helpful. You've got me thinking, because the flattened ceiling arrangement is what we have in the second bedroom and it does look rather lovely in there. But even though 9' is pretty high, above the temporary worktop we have a tall Victorian store cupboard that reaches almost to the ceiling, and I'm having trouble imagining life without that cupboard in the small kitchen. And I must admit that aesthetically I do really like the ceiling that follows the line of the roof. Insulated plasterboard is definitely an option, but I'm finding it hard to imagine plasterboard in the house as we have lath and plaster ceilings everywhere else and I do love them. Am I just being silly in considering a new lath and plaster ceiling? Should I be embracing plasterboard in this instance?

And Penners, you are funny (I know this to be a fact - been lurking on the forum for a while). Would really appreciate a photo of your kitchen, if you have the time / opportunity.

 

[Penners]

Mish - here's a photo of our galley-style kitchen. The room is actually a bit longer than the photo shows, but the bit where I'm standing with the camera is a little eating area. The bit you're seeing is the true kitchen and is, as I said above, about 7ft 6 in wide x 10ft 6 in long (right to the back of the cooker in its recess on the far wall). To see the full picture without the scrolling bar just click on it.

Mrs P seems pretty happy with this kitchen layout, in terms of its efficiency. I'm not sure whether that's a sexist statement, but there's absolutely no point in my pretending that I share in the cooking duties. I can burn water.

 

[Feltwell]

I can burn water.

Really? Blimey, forget Solar PV for cheap power, sounds like Penner's got a much better method sussed here. Either that or he's been getting plumbing tips from this chap.

http://www.youtube.com/watch?v=VEQMA0zwMM4&feature=related

 

[Penners]

It looks to me as though that chap has solved the world energy crisis.

Feeling chilly? Gather round the hosepipe and warm yourself.

 

[LadyArowana]

I can burn water.

Really? Blimey, forget Solar PV for cheap power, sounds like Penner's got a much better method sussed here. Either that or he's been getting plumbing tips from this chap.

http://www.youtube.com/watch?v=VEQMA0zwMM4&feature=related

I hope Joce doesn't see that, it will put her right off the borehole idea!

 

[Feltwell]

I hope Joce doesn't see that, it will put her right off the borehole idea!

Oh I don't know, given that her place will be getting colder every day at the moment it might just look quite appealing to her!

 

[vicky whitworth]

I always admire a managing director who is prepared to roll up their sleeves and do real work, especially one who leaves the workplace so neat and tidy. Hurrah for Mrs P

 

[Penners]

Hurrah for Mrs P

I agree*!





*I'm under orders to say that....