mgo

Here a quick update of the work so far we used 50mm woodfibre between the rafters, and a second 100mm layer (to be installed). The rafters are 110mm deep, giving about 50-60 mm ventilation between the woodfibre and felt. I will need to open up the eaves, as i dont see any particular ventilation system in place. Yet we are in one of the windiest locations in Ireland, so there should be a bit of a flow at al times. I left a gap at the top of the rafters above the collar ties, to provide ventilation between both sides, and insulated below this.

such a lot of info here, my wonder is do you always need to break up the old concrete floor? If you have enough headroom, what could be the disavantage to just add a layer of PIR insulation on top of the old concrete, add UFH and level off with screed. Leaving out DPM all together when the original cement floor is not damp. I am in the same situation (assuming no insulation / DPM currently under current old cement floor), and am looking into installing it this way, rather than opening up and excavating all excisting flooring.

here is a detail of the roof felt, would anybody have an idea what type this could be? I dont see any brandname anywhere outside of this there is 3-4 cm cavity and then the back of the slates

here you can see the wall / ceiling section

Thank you all for your quick reply, i have a few pictures, we took down the skim plasterboard walls and ceilings, which showed back the old ceiling still in place I dont know how to check what type of felt has been used, i would asume a vapour open, but am not 100% sure, no brand name is visible. The roof continues at an 45 degree angle, so there is +/- 120cm above the middle part of the old ceiling. We will open this up this afternoon hopefully. The roof exists further of slates on wooden battens, no solid layer is in between this and the outside as far as i can see. Wood fibre i am attracted to because of its moisture control characteristics. Now that we can see the wall situation, i am also wondering to install woodfibre against / between the wooden frame that has become visible.

I am starting to insulate the roof (consisting of slates and felt) of an old stone cottage that currently has no insulation. . One layer of either woodfibre or rock/mineral wool placed between the rafters (12cm deep) is not going to be enough in terms of insulation value, and while the rafters are only 12 cm deep, i will have to install two layers in a crossed manner. I am now contemplating about a different second layer of insulation on the inside, because of the cost of woodfibre, i thought of rockwool (dampopen). Is it ok to use two materials back to back and then finish with a vpl layer? If so, what would be the best order: rockwool between the rafters (on the outside), then wood fibre on the inside, followed by a vpl layer, or the other way around? assuming both materials can be installed directly against each other without any cavity. Are there any negative effects i am missing with using two damp-open materials on top of each other? the finishing layer is either going to be the original wooden planks (if we can restore them) or lime plaster. Thanks

Dear members, I am a new member and hope to learn from, and share experience with upgrading an old stone cottage in the West of Ireland. The house is a solid wall built land commission house, which are all fairly similar in layout throughout ireland. Our house has been dry-lined many years ago, which we intend to remove, and go back to the original high ceiling (still in place) and stone / lime walls. The roof was updated before we bought it, (new slates), yet no insulation has been installed anywhere i can see, just the dry lining providing some sort of air-heat bridge. The plan is to use mostly old style methods to restore the orginal look, yet to include and update to modern comforts at the same time, possible installing underfloor heating, and woodfibre insulation in the roof and on the inside wall sections. Also intend to install some method of mechanical ventilation. Best, Machiel