Is 60mm insulation enough?

summereire

Hi, we're about to renovate a building that is constructed with twin block walls with a gap in-between to allow some empty space and 60mm polystyerene insulation. We're wondering, in practice, is this enough insulation for it to be comfortable? Clearly with insulation more is probably better however it would be much easier to work with what is if performance would be at all acceptable. Thanks!

Calahonda52

What type of building?
Whats the expected occupancy?
What age is building
Re:
"Clearly with insulation more is probably better"

If, perchance, it is a house, have u boned up on these

https://www.nsai.ie/S-R-54-2014-Code-of-Practice.aspx
and
Part L especially as well as the ACD's here
http://www.environ.ie/en/TGD/

summereire

Thank you- I appreciate those references and will check them out. It's a single story building about 25 years old medical-related clinic so want it reasonably pleasant. What I'm really trying to get a sense of is what it feels like to be in buildings like that from anyone who has experienced it and how much heating was needed to keep it pleasant.

galwaytt

I'm going to guess and say 'no'. Better than none if course, but that's a 20+ yr old spec you're talking about- a long way from today's builds.

summereire

Yes it is all right. That being said from anything I've been able to read on this it was common to build buildings this way up until fairly recently meaning that there are presumably plenty of 100mm block / 60mm aeroboard / 40mm gap / 100mm block building in the country. Of course many of these will have been retrospectively upgraded but I'm sure many haven't been.

If we were building we would of course go for a high spec but as it's an existing building we'd prefer to leave it as it is if it's at all acceptable but obviously would rather not do the renovations we're doing and later realise that we should have done something at the time when it was less destructive.

Anyone out there living or working in a similarly spec building and what does it feel like and how is it to heat?

BryanF

It's the lack of continuity at junctions that'll cause potiental problems imo

summereire

BryanF wrote: »

It's the lack of continuity at junctions that'll cause potiental problems imo

Yes I was considering this- and I suppose there's no easy fix to that other than internal or external insulation that would wrap around/over those junctions?

The concern with external insulation is that it will come out as far or further than the roof protrudes making it look strange and hard to seal, and internal would on some walls come out in front of windows that are currently flush with existing walls.

I've heard that it can also be possible to pump more insulation into the 40mm gap left- is that okay from a thermal bridging point of view and can it be done with just a pilot hole for access? Presumably it doesn't solve the junction issue though?

BryanF

summereire wrote: »

Yes I was considering this- and I suppose there's no easy fix to that other than internal or external insulation that would wrap around/over those junctions?

The concern with external insulation is that it will come out as far or further than the roof protrudes making it look strange and hard to seal, and internal would on some walls come out in front of windows that are currently flush with existing walls.

I've heard that it can also be possible to pump more insulation into the 40mm gap left- is that okay from a thermal bridging point of view and can it be done with just a pilot hole for access? Presumably it doesn't solve the junction issue though?

It's possible, get a few quotes & read the product data sheets carefully

It is straight forward to alter the eaves if going with external insulation - but plan and detail all junction carefully!