Yes! Stretch ceiling will sit perfectly flat, and it never sags, bubbles, peels, flakes, moulds, or fades! It can be installed right over the sagging ceiling, or, if it is in danger of falling, you might choose to knock the existing ceiling out and then install stretch ceiling right over the empty space. You may also want to check to make sure that the floor above isn't sagging, in which case you may need to install a structural column or beam. We carry over 280 colours in high gloss, satin, matte, sandy matte, and canvas textured finishes, as well as translucent, iridescent sparkle, and we have the ability to digitally print any high resolution image on any of the above.

We have raked ceilings in our new split level extension that follows the fall of the land (and in the rooms that were part of the skillion sections of the old cottage) and I love the sense of space they give and also the fact that the inside reflects what is happening on the outside of the house. We have used ceiling boards (painted white – I didn't want to feel like I was living in a cigar box) both in the old cottage and in the new section and they certainly add an enormous amount of visual interest to the rooms as well. However, I endorse the comments about the added trickiness of light fittings. Pendants with rods are out and pay particular attention to the little rose/canopy thingies that connect pendants to the ceiling – make sure that they sit flush with the ceiling and don't have weird unsightly bits that you can suddenly see because of the angled ceiling. We have successfully used LED downlights with a recessed diffuser and dimmer switches to make sure there is no glare but if the raked angle isn't too extreme they are a definite possibility.

You never mentioned your budget that you're willing to spend. You could add a thicker fill backed insulation blanket - 50mm, 75mm or 100mm are the common thicknesses. Steep roof pitch so would need scaffolding, harnesses, etc.. which adds up quickly. Probably still not enough insulation though but probably cheapest option. Insulation under existing timber linings then reline over the top of that as some have suggested. Working at height though so would need scaffold set up again and working overhead is not fun nor easy. You could replace the roof with a sandwich panel roof. Try Versiclad or Kingspan or comparable. They have a polystyrene type of insulation between an outer metal roof sheet and a metal inner sheet. These are heat laminated together. Again different thickness available from 50mm up to 180mm is common. The 180mm has a R rating of 4.7 which is quite good. Again steep pitch, etc., probably need new ridge capping, etc.. Probably most expensive option...... Keep us all posted on your decision though!

Just a thought, have you checked your lovely flooring will persist under new cabinets or more importantly the gap created by the island bench. Possibly put a simple narrow breakfast bar (with power point of course) across a couple of the window sections, lovely to sit and look out of the window and preserve the look and the light. Then you would save some depth into the living space, as the current breakfast bar is quite large and deep.