Victorian Conservatory - window repairs

[CJ]

I have a traditional, long and thin (about 30 x 6 feet) Victorian conservatory but unfortunatley the window frames are completely rotten. In fact, I think it's only the vine that's keeping the whole thing up! :? Has anyone out there had a similar repair job done? And if so, was it successful and how much did it cost? Any advice would be appreciated. Thanks.

 

[yamin]

no help whatsoever, but can we see a picture? it sounds lovely, even if falling into 'elegant' disrepair!!

 

[AMc]

We have a long, wide Victorian vinery (a.k.a. conservatory) 8m x 4m or 12' x 24' ish. I can't offer a lot of advice other than I spent a lot of time talking with conservatory manufacturers who were initially enthusiastic about restoration before eventually admitting they wanted to knock it down and begin again.

Our sills are also rotten to pieces partly due to neglect and partly due to the vines outgrowing the holes cut for them which pushed everything out of line. A supplemental poycarbinate roof added 20 years ago helped to push the rafters out of the wall and bow the long wall It's only a long succession of bodged over repair and Victorian over specification that's keeping ours from folding in on itself.

We're converting this space into living space and so have to confirm with 2006 build regs - that means reglazing with sealed double glazing units. This will involve rebuilding the majority to cope with the weight and make the structure sound (Structural engineer consulted). After a lot of tooing and froing our RICS surveyor found a local joinery company who looked kindly on the old timber and have agreed to reuse as much as possible, supplmenting new timber to deal with the extra weight of the double glazing. They in turn have a glazier who is going to sort out the units and make them as visually close to the original as is possible in sealed units/

Quotes for replacement came from £30-60K for modular stuff installed, bespoke was £60K up, the initial quote for repair and reglazing is £20K which I expect to creep up but not too much.

If you're only using yours as a greenhouse then I would contact some local joiners and get them to come around and quote for cutting in new timber to replace the rot or replacing the rotten sections completely with new.

 

[CJ]

Thanks for taking the trouble to reply, AMc, this is really useful. I too have been advised to demolish and rebuild to comply with building regs as we also want to now use it as living space. I have been quoted 42,000 for a rebuild (re-using stone, tiles, etc) but I am reluctant to do this as I feel the character will be lost by inserting double glazed units to comply with the building regs (we've been told to do the same thing). At the moment we have lovely bumpy glass and delicate, moulded (and rotten!) glazing bars and I know the replacement will be a poor substitute but obviously more practical. A dilemma! I think your estimate of around 20,000 for the window repair sounds about right and I'll look into this first before I get the builders in........

 

[AMc]

Don't take my advice as golden as I'm not a professional and interpretation of the regulations can vary a lot...

At this point I would...
- talk to an architect or two who is experienced in period properties AND understands Part L1B - Not all I spoke to did and some were woefully out of date.
- You could also try a RICS surveyor (which is what we've done) as I found ours to be knowledgable and easy to work with.
- Follow up by contacting a couple of local joinery companies to find out what they can do to repair and double glaze what you have. There is no reason that a competent joiner can't reuse what is still sound in your conservatory and replicate the moldings on the new wood, but unless you can secondarily double glaze I think your wobbly glass isn't going to make it.

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If you're going to live in your conservatory, heat it and comply with regs. you're going to have to double glaze. If it's not currently living accomodation you may find it almost impossible to comply with PartL1B of the current building regulations even if you do! It's worth bearing in mind that building regulations are likely to get more and more stringent as they move towards 'carbon neutral' targets so it may be now or never to get approval for this kind of work.

I had quotes for new conservatories (16mm double glazed, argon filled with low emissivity glass) with an overall U value of 1.8Watts/m2K this compares with 4.8Watts/m2K for single glazing* and 0.16Watts/m2K for an insulated pitched roof*.
The U value is the speed with which heat is lost through 1 square metre with a 1Kelvin temperature difference across the two faces, lower the better. Broadly speaking this means that you lose 30 times more heat from a single glazed roof as a modern solid roof. Even a modern double glazed roof loses over 10 times as much heat as a modern solid roof.

If you make significant repairs to a 'thermal element' in the living space i.e. a window you are obliged to bring it up to the current regulations unless you have a conservation area or listed building exception. Significant work is often interpretted as anything more than applying a coat of paint or replacing more than 25% of the glass or frame. In walls painting is not, replastering can be. If one took the amount of actual sound wood and glass as opposed to 'peat' and empty space in my frames I might have a case, but I don't think that works

You also need to take into account that if building control consider this an extension/change of use (as it's not currently living space) not renovation they may press to apply the guidance to limit the area of glazing to no more that 25% of the floor area - hard to meet with a mostly glass structure :0


Your alternative is to keep a thermal seperation between the house and conservatory (e.g. exterior grade doors and windows) and do not fit a permanent heating system. This would mean the conservatory would not be considered a 'room' for building control and would not need to comply with thermal efficiency. We rejected this on the basis that a £30K greenhouse wasn't going to recoup our investment if we decided to sell nor be comfortable to sit in most of the year.

Irrespective of how one may feel about the requirement for old houses to conform to modern standards of thermal efficiency turning a green house into a living room isn't really going to work without some changes - if you're planning on heating and using a conservatory you need to take into account that it will cost you more than twice as much to heat if it's single glazed not double glazed, given the price of fuel that's not an inconsiderable point. If you use a fan heater, oil radiator etc. then those costs in £ will be much higher as they are substantially less efficient in £ per Watt than oil & gas boilers.

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Our work is part of a larger renovation which allows us to go for an alternative method to prove complicance based on the 'whole house'. You can get the combination of the planned work and existing house assessed in comparison with the house and new extension the same size that all meets building regulations element by element. If you can show that the plans will perform equally or better than the standard in terms of overall energy use you can go ahead anyway.

In order to comply with the regulations we are fitting an air source heat pump and dumping the oil boiler (horray!). We're also insulating the walls, floors and roof of the half the house under renovation beyond building regulations standards and secondary glazing all the windows. We're also insulating the suspended wooden floors in the main house and digging out and insulating a solid floor (underfloor heating goes in throughout). We already have double glazing in the main house, some roof insulation but no wall insulation. We are also adding a wood burner into the conservatory as this helps with 'green' compliance as it's seen as carbon neutral (and I figure if it gets cold in there I can get a few logs on!).

Taking all this into account a SAP calculation (Standard Assessment Procedure) for our proposed works (with all that energy saving insulation and glazing and a 'green' heat source) we only just scrape through against an extension of the same floor area with oil. I don't have approval yet, though the application is in.

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* values taken from The Green Building Bible vol2

 

[MdB]

When working out whether or not you meet the regs, its worth noting that the figures are based on the ratio of energy being used to heat the property to the amount lost. This means that if you have high losses you may still be able to meet the regs if you have a highly efficient heating system. The obvious one for this is a ground source heat pump as that is considered to be very energy efficient (if used correctly). Pretty much any house however insulated meets the regs with a ground source heat pump.

This site (http://www.playtheregs.co.uk/) is rather useful for playing around with different options to see what is possible. Use bill@microsoft.com for the email address and get a feel for what you need to do. The conservatory is completely outside of what this simulation provides but it may still be useful to you. You can put a glazing area of 40% into the simulation which might not be too unrealistic for the whole house.

 

[AMc]

Pretty much any house however insulated meets the regs with a ground source heat pump.

Indeed. The GSHP or and Air Source HP both notionally offer 3-4 times as much heat output in KW as electrical energy input in KW so they can be used to offset comparitively inefficient buildings. The basic idea being you'd be creating more carbon emmissions heating with oil or gas than with electricity than the 'free' heat you're extracting from the ground/air. You have to bear in mind that Watt for Watt electricity is more expensive than oil and gas so you'll not be cutting your fuel bill down by 75%.

We're going for air source because we don't have the land for a large enough slinky. We've been told to expect heating bills on a par with oil for the same house. Which given the increase in space and that great chunk of glazing is likely to be quite big.

Even with that in mind and plans to heavily insulate the house our vinery puts us on the brink of non compliance. If the existing windows weren't double glazed and the walls and floor weren't being insulated in the new work we'd be stuck unable to use the vinery.

I'll check that site out - looks like an interesting toy!

 

[chuckey]

What is the orientation of your greenhouse? because if it has a lot of sun falling on it, it can overheat in summer. My double glazed conservatory ( triple wall polycarbonate roof - OK, it was cheap) reached over 105 deg F on a summers day before I installed thermostatically controlled ventilation, now its gets to 80. In the spring and autumn it could be a good source of heat for the rest of the house if proper ducting/fans were installed. Won't get done now, I have moved onto bigger things.
Frank

 

[Flyfisher]

When working out whether or not you meet the regs, its worth noting that the figures are based on the ratio of energy being used to heat the property to the amount lost. This means that if you have high losses you may still be able to meet the regs if you have a highly efficient heating system. The obvious one for this is a ground source heat pump as that is considered to be very energy efficient (if used correctly). Pretty much any house however insulated meets the regs with a ground source heat pump.

Is the electricity provider taken into account as well? A heat pump powered by Ecotricity, for example, would appear to be completely carbon neutral, regardless of the construction of the building.

 

[MdB]

Is the electricity provider taken into account as well? A heat pump powered by Ecotricity, for example, would appear to be completely carbon neutral, regardless of the construction of the building.

I don't believe the regs take that into account.

 

[AMc]

The regs can't take your provider into account as the next family could switch to a regular coal/gas/nuclear tarrif.
In the same way you are required to fit 25% of light fittings that phyiscally can't accept a standard Edison screw of bayonett bulb. Even though you can fit energy efficient CFL bulbs in standard fittings, there's nothing to stop the next guy from fitting a tungsten filament bulb and the process is about the lifetime energy consumption of the building.

If you fit micro generation equipment like a wind or water turbine, photovoltaic or hot water solar panels then these can be used in the whole house calculations to offset other less optimal things like solid walls and a glass roof. A heat pump is classed as a micro generator as it creates more heat output than it consumes.

Our heat pump will eventually be powered by http://www.good-energy.co.uk - they claim to be the only supplier who match every watt sold with a renewable watt purchased.

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@chucky - What size orientation do you have and how much ventilation did you fit?

We've already committed to rain sensing/thermostatically controlled vents as summer overheating when the house is unoccupied is a big concern. Ours is facing due East so I'm hoping for a positive solar gain in the morning, stored in the insulated pammet floor and exposed brick internal wall through most of the year. The room will be shaded by the house from about 1pm so I'm hoping overheating won't be too much of an issue. The low emmissivity glass should help by allowing ultra violet in, but reflecting infrared back in.

Unfortunately as I understand it SAP and building regs take no account of passive solar gain. It's very hard to model accurately and obviously you get the most free solar heat in the summer when you need it least.

 

[chuckey]

Its a leanto, on a west facing wall. The windows facing west are 2.5m high X 5m long . One side faces south 2.5m high X 2.8m wide. - all glass Pilkington 20mm double glazed K glass. Roof 50mm triple wall polycarbonate with "milky" colour (5m wide X 2.8 deep).
I know a couple of chaps who had to have their glass double glazes conservatory roofs covered in solar film, one professionaly done*, one DIY. Both achieved a useful reduction in temperature. I don't think that solar film will adhere to Polycarbonate, hence the fans.
* I think it costed about £40/sq. m
Frank

 

[Flyfisher]

The regs can't take your provider into account as the next family could switch to a regular coal/gas/nuclear tarrif.

I suppose there is some logic in that, although the next family might keep the heating at 80F and leave all their windows open (if they are millionaires, that is) or they might only heat one room to 60F and wrap up warm, which could easily have a far bigger effect than the electricity tariff. But I guess the regs can't control everything.

Our heat pump will eventually be powered by http://www.good-energy.co.uk - they claim to be the only supplier who match every watt sold with a renewable watt purchased.

I wonder who they buy it from? According to http://www.ecotricity.co.uk/about/our-progress/ they don't seem to invest in any renewable capacity themselves.

 

[AMc]

Our heat pump will eventually be powered by http://www.good-energy.co.uk - they claim to be the only supplier who match every watt sold with a renewable watt purchased.

I wonder who they buy it from? According to http://www.ecotricity.co.uk/about/our-progress/ they don't seem to invest in any renewable capacity themselves.

They own their own windfarm and buy in from other renewable generators and micro generators. They are currently seeking planning permission to replace their existing turbines with fewer, larger, more efficient models.
I don't think they have enough customers to appear in that list, but then as green as both Ecotricity and Green Energy are I doubt they would promote each others offerings.

Sources of our renewable power
Good Energy sources renewable power from wind farms, small hydro power stations and solar photovoltaic installations across the UK. At the moment this includes generators in Cornwall, Devon, Cumbria, the Midlands, North Wales and Scotland. The current mix is approximately 92% wind power, 7% small hydro and 1% solar. We also own our own wind farm at Delabole in Cornwall.

http://www.good-energy.co.uk/factfile_renewables#1