Advice on Sunroom Insulation

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DazzaMazza

Registered User
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Hi All,
I need some advice on insulation for an existing sunroom. Our house has a sunroom which is well served in terms of rads. However the ceiling is 16ft high and initial inspection suggests that there is about 100ml of rockrool in the ceiling.

I hope to have a budget for improving the sunroom before another winter arrives and we need to basically close it off. What I am wondering is

1. Would it make economic sense to replace the rockwool insulation with thicker kingspan style boards and if so would it make a difference.

2. Would it make a difference if we lowered the internal ceiling?

Any advice from you would be well received!!

Many thanks

Dazza
 
There are a number of factors to consider in addition to the existing insulation in the ceiling and the ceiling height.
For example,
What are the u-values of the existing windows and exterior doors?
What percentage of the exterior walls are made up of windows and doors?
What is the overall interior volume area that needs to be heated?
Is there insulation under the floor?
Is the sunroom south facing?
If the u-values in these areas are poor it may make only a marginal difference if you substantially increase the ceiling insulation and also drop the ceiling height.
SEI were up until recently giving grants to avail of a registered energy assessor, I don't know if these grants are still available. It maybe money well spent in getting an overall assessment and calculations done before you go spending money an renovations.
Finally dropping the ceiling may take away from the ambiance of the room.
 
yikes, 16ft is tall !!

100mm insulation in the roof is nowhere near enough, and I wouldn't be keen on ruining your room by pulling down the ceiling. What you could do, though, is build a new false one, retaining your existing style, at 15', or 14'6", and insulated the bejeebus out of that. It would also be one of the easier things to do, compared to say, adjusting floors, or walls, or windows.
 
The easiest, cheapest and most effective method would be to add a layer of 150mm rockwool insulation above the ceiling over the existing, then screw thermal lined boards beneath (overboarding) to the ceiling into the existing joists and skim. Why bother creating a new ceiling when there is one there already to be utillised ??????
I can not visualise a room with 16ft ceilings, do you mean a room with a vaulted ceiling which is 16ft at the apex, as a room at 16ft has 16ft windows (sunroom) and no amount of insulation to the ceiling is going to make a warm room without first upgrading the windows to a very high spec which would be extremly expensive.
 
Yes I should have been more specific. Its a pitched cathedral style roof and the roof is approx 16ft at its apex. Thus I think I would need to either

1. Remove existing insulation and add greater levels of insulation (kinspan boards etc)
2. Build a false standard ceiling and insulate that well. Sure I'd loose some of the room ambiance but I think this might be warmer.

Thanks for feedback
Dan
 
Dazza, now were cooking with gas !
It is not a traditional ceiling so ignore my first post.
I have or had exactly the same problem as you, I built my house and the rear room single storey had a vaulted ceiling and I insulated between the rafters using Kingspan rigid insulation and boarded it with regular plasterboard and skimmed, in the summer it was the coolest room in the house when the weather was hot as the insulation reflected the sunlight....great, but in winter it was absolutely freezing.
Yours would be even colder I assume as Rockwool does not compare to rigid Kingspan.
The main problem for me, and yours may well be the same, were the recessed lights I had....six in all. These are akin to having six holes in the roof as naturally there is no insulation around them as this is a fire hazard so the first thing to do is get rid of those lights if you have them.
I then cut open the ceiling and insulated where the lights had been, in your case I would strongly suggest you take down the plasterboard ceiling and replace the rockwool with Kingspan rigid insulation, immediatly you have at least doubled the insulation value of the original.
You should then use 48mm insulation backed plasterboards over the rafters, which all in all will give you're ceiling an excellent u value (no draughty gaps from recessed lights). If you have any wall areas you should dry line them again with 48mm boards.
I can assure you this will create a very cosy room, probably the warmest in the house, I am speaking not only from my experience but as a builder plasterer who was kicking himself for not going the extra mile when doing the room in the first instance, now the room that could not be used at all in the winter is a football watching haven from screaming kids lol
 
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