Must new extension meeting air-tightness requirements from building regs?

metricspaces wrote: »

If getting a small extension (30 sqm) on an existing 100sqm 50 year old bungalow must you do air-tightness on the extension?

Extension is exempt from planning. Legally where does this lay in terms of building regulations? Does the extension have to meet current building regulation (for air-tightness, and for everything else)?

It would obviously be a good idea to do airtightness (and satisfy all other building regs where possible) even if not required, right?

Air tightness: limiting air infiltration
through the newly constructed elements
as far as is practicable. Guidance is
given in sub-section 2.1.4;

metricspaces wrote: »

Thanks. I took a read and my understanding is that there are no specific requirements to make an extension as I described airtight. There's no figure specified that should be met.

Based on this it sounds like for an extension as I described there's no requirement to use airtightness materials, but doing so is a good idea. Sound correct?

metricspaces wrote: »

Thanks. So makes sense to use airtighness material and tapes on new extension.

The plan for the existing house is to replace windows\doors and do internal insulation with drylining.

What would be the most feasible\practical thing to do in terms of airtightness of existing house?

I guess even if no airtightness material on walls of existing house, it would make sense to use airtightness tape around reveals after installing new windows\doors?