Convert Conservatory to Extension?

[RBZ5416]

We have a lean-to style conservatory built on a dwarf wall. It's approx 4m x 3m, double glazed in hardwood frames with a single cell polycarbonate - and it's good for nothing! It's south-east facing so in the summer, the sun hits it almost a soon as it rises & doesn't leave it until around 16:00. It reaches 50°C+ in no time. In the winter it is literally freezing.

I've had a ball-park figure of £20k to replace it with a single storey extension but this seems excessive. This is based on nothing more than it just doesn't look like that much work to my (totally untrained!) eye?

It would need a radiator & electrics. There's a rad on the party wall with next door that could be extended from & there's already a couple of mains sockets on the conservatory. No other plumbing required.

I'd really appreciate some feedback on costs as all of the local builders I have contacted (Colchester) have failed to call me back.

I'm wondering if we could keep costs down by retaining the current outline, using the existing footings & building up from the dwarf wall. Is this likely to be feasible?

 

[RedHerring2]

I would guess, and bearing in mind, I'm only a DIYer, the conservatory was not built to Building Regs, whereas the extension will have to be.
So, perhaps, your quotes received so far, are based on that assumption.
Building Regs will apply to your footings, (depth, width and thickness), floor slab, wall construction, etc.

I would also guess that by the time you've excavated for inspection you might as well start all over.

And don't forget costs associated with disposing of waste.

 

[noseall]

I'm wondering if we could keep costs down by retaining the current outline, using the existing footings & building up from the dwarf wall. Is this likely to be feasible?

If the connie has been built to typical connie base installation quality, then i would say no.

It is better to trash what's there and start again.

Building control would ask to see a test dig to expose the existing concrete footing to ascertain suitability.

 

[Deluks]

20k is in the right area for single storey ext. If you advertise the conservatory on ebay, buyer to dismantle & collect etc then you might shave off a couple of grand, plus whatever you get for the old conservatory.

You saying it's good for nothing, a conservatory is a glazed room for keeping plants in, which I imagine it is very useful for.

 

[RBZ5416]

You saying it's good for nothing, a conservatory is a glazed room for keeping plants in, which I imagine it is very useful for.

Not that many plants that are equally at home at both 0 & 50°C though.

But we digress.

 

[RedHerring2]

Have you thought about re-glazing it, perhaps in triple/quadruple wall polycarbonate, assuming the frames are suitable.

I don't know how any difference in heat loss would work out or the costs associated with the re-glazing, but worth an investigation, perhaps.

 

[RBZ5416]

Heat loss is only half the story as an equal (if not greater) problem is trying to keep it below roasting on a sunny day.

I suspect that no matter how efficient the glass was it would still cost a fortune to heat in winter & cool in summer.

 

[RedHerring2]

Heat loss is only half the story as an equal (if not greater) problem is trying to keep it below roasting on a sunny day.
.

Blinds

 

[RBZ5416]

It had vertical blinds fitted all round when we bought the house. Even tying up a large dust sheet to the roof as well made precious little difference.

I suspect I would need to stop the heat entering in the first place. I've even looked at a big awning.

One thing that may do it (that I've never really researched) is a blind between the glass. I used to work in an office that had double-glazed partitions with integral micro venetian blinds. But then it would be pitch black in there & the lounge.

It's gotta go!

 

[conservatorysurveyor]

conservatories always used to be fitted with the cheapest sealed units and polycarbonate, but due to customer pressure they can now be fitted with better insulated glass than is used in windows. I'll send you some information if you want which explains it better.

 

[noseall]

No matter how much money you spend on glass and blinds etc it will still be a glazed connie that will still be freezing in the Winter and a furnace in the Summer irrespective of Pilkingtons finest.

There is no miracle glass available. Some glass may be an improvement on what you have already but be prepared to be disappointed.

So if you have a building that is mostly glass or polycarb, it will act just like a building that is mostly glass or polycarb.

 

[RBZ5416]

No matter how much money you spend on glass and blinds etc it will still be a glazed connie that will still be freezing in the Winter and a furnace in the Summer irrespective of Pilkingtons finest.

There is no miracle glass available. Some glass may be an improvement on what you have already but be prepared to be disappointed.

So if you have a building that is mostly glass or polycarb, it will act just like a building that is mostly glass or polycarb.

My sentiments exactly.

 

[conservatorysurveyor]

I must disagree with the last couple of posts, modern glazing can give u values that are better than cavity walls ( cavity wall without insulation = 1.9 - celsius one double glazed units = 1.0) ok the target for new build regulations is .35 for cavity walls but thats in a perfect world.

 

[^woody^]

I must disagree with the last couple of posts, modern glazing can give u values that are better than cavity walls ( cavity wall without insulation = 1.9 - celsius one double glazed units = 1.0) ok the target for new build regulations is .35 for cavity walls but thats in a perfect world.

But the point is that [bare uninsulated] cavity walls are not acceptable nowadays, so a glazed wall does not have comparable or acceptable u-values compared to those required from a modern masonry wall

In addition there is no thermal mass in glass, so temperature changes are rapid and at the whim of a bit of sunshine and shade

OK, there could be a SAP calc on the whole property to make the property as a whole achieve an average u-value, but that will not alter that fact that the glazed conservatory will be a cold or hot room, prone to draughts, prone to extreme temperature changes, and requiring a lot of heat to maintain a comfortable environment

It will be OK for the Yucca though

 

[hotrod]

I must disagree with the last couple of posts, modern glazing can give u values that are better than cavity walls

Utter tosh, do you honestly believe that or are you knowingly telling porkies?

( cavity wall without insulation = 1.9 - celsius one double glazed units = 1.0) ok the target for new build regulations is .35 for cavity walls but thats in a perfect world.

1. What type of cavity wall construction (insulated or non-insulated) would give 1.9W/m²K?
2. In what circumstances would a new build cavity wall be non-insulated?
3. Target U-value for new build walls is 0.30W/m²K not 0.35W/m²K.

Come on, conservatorysurveyor stop trying to pimp your ride