Renovating 1840's cottage

[katjam]

Hi all,

We are in the process of stripping out an old cottage that we bought 2 months ago, although with 2 young children and my husband working full time its a slow process. We have so far stripped the most of the cottage back to the stone walls and are working on the last room now. We have decided on the layout and extension and the architect is finishing the plans in the next few days. I have been reading many of the posts on here for the past 4/5 months and it has all been really helpful but I'm hoping by running my plans past you all someone might spot anything I've missed before its too late !?

We are short of space in the existing cottage so we are restricted on insulation, bus basically we are re-framing the cottage walls with 50mm kingspan K12 in the frame then 50mm K18 on top and will be sealing and taping carefully. The ceiling of the bungalow is just some wooden paneling there is currently no insulation at all and I'm still trying to decide what to do for best. Similarly the suspended timber floor only has about 25cm below it so I was thinking about attaching netting and siting rock wool or similar on top.....but I would like a completely sealing insulation box within the house and sealing the soft insulation to the rigid boards is confusing me...as is getting around the cold bridging from the floor joists ?

As far as ventilation goes I am hoping the by leaving a 30-50mm gap between the walls and the framing that the ventilation around the outside of my box and sealing the insulation well that it will be enough to keep the walls dry ( or as dry as they get..stone walls and lime mortar.)

In house we will be having two viking house 'breathing windows' and on there advice a humidity motion sensor extractor in the bathroom.

I could go on for pages but if you've made it this far then well done ! Any thoughts/advice much appreciated

 

[freddiemercurystwin]

100mm of Kingspan insulation in the walls may be a little excessive, but will certainly be toasty.

For the ceiling we assume the ceiling is just flat. Normally 3 years of Rockwool will do the job for the ceiling, add more layers if you wish but once you add many more it will reach a point where the payback gets much small with each layer. The obligatory keeping the eaves vents clear comments apply, if applicable.

When renovating an existing timber floor, you cannot avoid the cold bridge of the joists. I wouldn’t worry about it. Buying insulation seconds from various companies or ebay may save you a small fortune. Whilst Rockwool on chicken wire is effective, about 80mm of Kingspan wedged into the gaps and any tiny gaps sealed with expanding foam will be more air tight and less draughty, especially with foil tape over any joints. We assume you have a couple of air bricks to vent the void beneath the joists.

A good dose of sealant around all openings, plug sockets, skirtings, under plasterboard at floor level and anywhere else will all help ensure air tightness but do not forget adequate ventilation too, or condensation problems may arise.

 

[katjam]

Thank you for the reply, my husband and the architect are in agreement with you over the 100mm kingspan being excessive...but my student days were spent in an old rented farmhouse with no insulation, some broken single glazing, 2 open fires and lpg gas for heating....I spent 2000 on heating Decenber to January (and still froze) and as much as I love the charm that this old cottage has I will only love living in it if I'm cosy !....2 months of moaning wore them down enough for me to win this argument.

Re airbricks under the house...there are none that I am aware of...but there are large open vents...I was hoping to just put on new vent covers and put a fine mesh behind it to try and stop mice from visiting ? I was hoping that between them and the eaves air would circulate all around the house? but I could well be wrong..and I'm definitely lacking knowledge in this area as previous experience has only gone as far as some new plasterboard on walls and fitting a kitchen