Closing off big gap between joists and top of wall in loft

[Montcigoux]

Hi all. Any suggestions for the best way to do this. I am converting a very old first floor grain loft to a sitting room and eventually the space between the joists will be insulated. Ideally although it is more fiddly work and cost I want to leave the old wooden roof joists exposed rather than covering them with plaster board. But there is a big gap where the end of the joists meet the top of the thick stone wall of several inches to be closed off first and from experience it needs to be animal proof. Even fixing insulating board to the underside of the joists thus hiding them would leave a big gap. I was thinking of using those thin red large tile size bricks bedded into mortar on top of the wall and the top of the brick would then meet the underside of the roof tiles. Any thoughts or suggestions or previous experience please? Bear in mind that I am female and not as strong as the average man. Thanks

[Théière]

If you could post a picture or two it's always helpful. Assuming I do understand you correctly then what you are proposing would cause a cold bridge from the roof to the wall which is to be avoided where possible and especially if you are going to insulate the rest of the roof as cold air will condense on that spot and mold growth would be the likely result.

To animal proof I use stainless steel mesh but small areas can be stainless steel kitchen scrubbers bedded in mortar or broken bottles/crushed glass.

[Quillan]

Roof voids have to breath is the first thing but as you won't be having a ceiling blocking them in won't be a problem. The thing with grain lofts is they need ventilation which is probably why they have not been blocked off before. If you are converting a previously non habitable area into one then the new regs RT2012 are applicable. Look for the thread about the guy and his stone walls there is information there. You can also Google RT2012. Your biggest issue will be the mandatory insulation which may mean that the 'feature' of the exposed beams may not be a reality and you may have to insulate, plasterboard and put up fake beams. If that is the case then you might not have to do anything other than put up mesh as the void would be effectively almost, but not quite, blocked off by the insulation and plasterboard. Don't forget to leave the insulation a little short of where the roof meets the ceiling to allow for a little ventilation between the insulation and roof. I am sure others here may well be able to give you more suggestions on what to do at a more practical level as my 'hands on' experience of RT2012 is extremely limited.

[NickP]

RT2012, there is on another forum a suggestion that this "rule" is now in the process of being changed, and will not affect buildings under a certain sq footage, so I would check that out. Stopping animals getting in? you will never stop the small ones but the ones to stop are the Fouine and squirrels , to manage this our man blocked entry points with Zinc plates. and when we had the roof renovated with old tiles (site historique) we were allowed to add roof vents that had anti animal grills fitted.