Renovating old house to 'A' Energy Rating

derickmc

I am after purchasing a 3 bed terraced house in Cork City. The house is nearly 100 years old and needs complete gutting. It is about 1200 sq feet and has 2 stories.

I want to get as close to an 'A' rating as possible. I would be grateful if any could advise me on the following.

• Heating - the house is supplied with mains gas, I presume a condensing boiler is the way to go here - any recommendations as to what type / what to look out for ? Is solar for space heating a waste of time ?
• Water hearing - are solar panels maybe. The back of the house gets good sun light. Evacuated tube or flat Panel - I was given a big sales pitch on Evacuated tubes being best in the northern hemisphere but have since heard the opposite. - any advice appreciated.
• Walls - will need to be dry lined - what would be the best material here. At the moment they are a miserable 10' breaze block !
• Attic - what is the best insulation ? Sheeps wool ?
• Floors - there are 2 types of floor on the ground floor, a suspended wooden floor on joists over clay with no insulation and a solid concerte floor ? What are the best options here ?
• Renewable energy - is a small wind turbine worthwhile, if so where would I find info on this ? Are PhotoVoltaic panels any good ?
• Ventilation - at a loss here at the trade off between well aired and cold - any advice appreciated ?
• Windows - 16mm argon filled double glazed I hear are the best. Any advantage to going triple glazed ? Less solar gain I hear but surely a better U-Value ?
• External Doors - any recommendations.

Also I am hoping to carry out much of the renovations as possible myself - insulating, drylining etc. Is there any danger this could invalidate certain work - i.e. could it need to be carried out by a certified tradesman to be allowable fot the BER ?

Thanks in advance,

Derickmc

Slig

Not to sound discouraging butI think you should forget about the energy rating and decide what changes you want to make and what you can afford. You are looking to make a morris minor into a supercar. It can be done but will cost a fortune, you will end up making huge sacrifices and the end result will never be as good.

Sheeps wool is a grand insulation solution but you will need huge quantities to compete with the more conventional brands and it is also more expensive.

Dry lining is definately going to be a problem as you will need min 150mm joists (not studs) with insulation between to achieve anywhere near the required u-values. This will take room off the interior of the building and lead to trouble where internal walls meet external walls. Same with the ground floor which will have to be insulated.

Then there is the HRV system, which will be required if an A rating is needed. This will require the house being air proofed.

Basically you will essentially need to strip everything out of the house until your left with bare external walls and essentially build another house inside these.

It is probably a better idea to investigate what you can afford in terms of insualtion, windows doors etc., an effecient heating system and controls etc.

getfit

Slig wrote: »

Basically you will essentially need to strip everything out of the house until your left with bare external walls and essentially build another house inside these.

well put.

Chimpster

getfit wrote: »

well put.

Contact a registered BER assessor. Ensure that he has done this type of work before. Check his background.

Get him to provide a BER spec for getting the house to an A rated standard. It can be done. You are essentially starting from scratch but at the end of the day this house can become as enery effecient as a new house assuming proper guidance is given.

derickmc

I see your point though, no point in throwing good money after bad trying to reach the unattainable. Can't make a silk purse from a sow’s ear and all that.

My plan is to strip everything out of the house apart from the first floor, internal walls and stairs.

I am guessing a B rating on such a property would still make it very attractive would that be realistic ?

On the dry lining are you sure the assessment factors in the break in insulation where an internal wall intersects the insulation on an external wall? I was under the impression that the BER system would not factor this in and it would count as a fully insulated wall ..

With a B rating in mind, could I cut down much on the insulation?

[FONT=&quot]I had been thinking about studs with Rockwool (50mm) between them and insulation slab (50mm) over them to end the thermal bridge caused by the studs? [/FONT]

sydthebeat

when calculating u values of walls you have to account for thermal breaks... ie studs battens ties etc...

its admirable that you are focused on achiving a high rating.... but to be honest i think you need professional help... (in the good sense!)

engage an architectural technician that is also an energy assessor and let him advise on the best way to achieve a well air tight house with a good level of insulation.

IMO an airtight house with adequate insulation with a HRV system is best for your situation. To do this will conserve a significant amount of energy, leading to the fact that you could negate any use for an 'expensive' renewable technology....

sinnerboy

Assuming your house would achieving a BER E2 rating your approx gas bills* will be
120m2 x 340kwh/m2/yr * €.061 = €2592.00

If you upgrade to BER C2 rating your approx gas bills will be
120m2 x 340kwh/m2/yr * €.061 = €1302.00

If you upgrade to BER A3 rating your approx gas bills will be
120m2 x 50kwh/m2/yr * €.061 = €366.00

* http://www.sei.ie/Publications/Statistics_Publications/Fuel_Cost_Comparison/Domestic%20Fuel%20Cost%20Comparison.pdf

However your extra over capital spend to get up to A3 vs to C2 is unlikely to justify the return in fuel costs savings

Solar panels make sense . Evac tubes produce more than flat on a per m2 panel area basis - but in my opinion look terrible . Flat is bound to be more architectural pleasing in you case and in m2 terms cost less - so use more m2 . Allow 1.5m2 per person ( flat )

Be carefull not over over do it on dry lining insulation thickness - you may get condensation forming behind the insulation on the surface of your wall .
Use a breathing insulation between terated battens and use Intello/Siga or Vario membrane over the insulation before you plater board over . Either of those membranes will allow the wall to breath to the internal and will assist with air tightness

If you can afford it rip out your timber floor including joists under and hack up your concrete floor and insert a radon barrier , min 200 exp poly insulation and new 150 concrete slab over .

Google SEI Harp Database for info on efficient gas boilers

A BER assessor will require EVIDENCE of works done if you engage one after the event. Either works signed off by a building professional and/or extensive and clear photographic eventide . Your best bet is a BER Assesor who is also a building professional who will oversee the lot

Wind turbines and pv's have a long payback period

RKQ

Some very good advice above.

Have you considered or costed external wall insulation?
Cills would need to be extended but if you are gutting it maybe new cills aren't a bad idea.

At the end of the day costs of materials V's payback. Value of completed property is more important than having an A1 rating - no point in spending double or triple the amount if the value doesn't make it viable or worthwhile.

derickmc

[FONT=&quot]Thanks lads. Good advice on the insulation sinnerboy. Definitely puts me on the right track.

RKQ -
I briefly looked into getting the house I am living in insulated and it seemed very expensive. Over 8k for a small wall 12 ft long x 16 ft high. there was some plumbing on the wall so there were pipes that needed to be extended also windows and rafters needed to be lengthened and the sofit and fascia was to be replaced too. I though it was very expensive.

In this case I am in a terrace so I'd say I wouldn't get planning as I would be bringing the front of the house out beyond the neighbours.

sydthebeat -
You are recommending getting in a HRV system Do you reckon that the regular passive vents a big problem then? I was thinking that myself. Would that have a decent impact on the rating? I believe they are expensive..[/FONT]

bamboozle

just started a renovation job plus putting on single story extension, we wanted to do as much as we could afford....
what we've gone for is 70mm Kingspan K17 Cooltherm insulated plaster boards on interior of all external walls, reinsulate attic (cant remember off hand what spec)
solar panels
multi fuel stove with back boiler linked with downstairs rads,
for extension twin leaf cavity wall with 60mm kingspan K8insulation inbetween.
Extension floor Kingspan tf70 floor insulation
Replaced all windows with A rated windows.
Removed 2 North facing windows.

no doubt we're nowhere near an A rating but when its done it will be a huge improvement on what it was, we didnt bother going for a new boiler and spent the extra on insulation.

sydthebeat

derickmc wrote: »

sydthebeat -
You are recommending getting in a HRV system Do you reckon that the regular passive vents a big problem then? I was thinking that myself. Would that have a decent impact on the rating? I believe they are expensive..[/FONT]

yes derick... they will cost about 4k.... and compared to a basically 'free' hole in the wall its hard to argue but.....

with a passive vent the air in a room is changed on average 4 times every hour.
so that means the heating system needs to heat the whole room 4 times every hour... keeping it simple...
a HRV system uses already heated stale air in the house to preheat fresh air coming into the house...

so just say a HRV system is 80% efficient... that means in 1 hour the heating system only needs to heat 20% of the room... so it would take 5 hours before the whole room is heated with complete new heat from the heating system....(5 x 0.2)
now if passive vents were used that 5 hour period the heating system would need to heat the whole room 20 times (5 x 4)

so using SBs example of gas above.... if it costs 20c per hour to heat a room with passive vents, it only costs 1c per hour to heat a room with a HRV system.

Thats very simplified and theres probably some who will question it, but thats the way i see it.

Mellor

bamboozle wrote: »

for extension twin leaf cavity wall with 60mm kingspan K8insulation inbetween.
Extension floor Kingspan tf70 floor insulation
Replaced all windows with A rated windows.
Removed 2 North facing windows.

What are A rated windows?
I've heard this before, and had a feeling that it was a sales pitch from a guy who had no BER knowledge.
Hopefully, its an EU designation. And there are some sort of limits that must be met, but i'm not 100% on that.

mlelsc

Why not ring the dept of environment and ask them for advice as the currently have new regulations coming in and are supposed to have advisors on these matters.
ask your friends do any of then know Doncan Stewart as he is brilliant in this area!
Sorry I can't be of more help to you.

bamboozle

Mellor wrote: »

What are A rated windows?
I've heard this before, and had a feeling that it was a sales pitch from a guy who had no BER knowledge.
Hopefully, its an EU designation. And there are some sort of limits that must be met, but i'm not 100% on that.

I stand corrected as the windows have been in a few months so i've forgotten the finer details...BUT if i remember correctly they have a u value of less than 1.1 for the glass, think the rating came from the British window council or some crowd with a similar name.

Slates

sydthebeat wrote: »

yes derick... they will cost about 4k.... and compared to a basically 'free' hole in the wall its hard to argue but.....

with a passive vent the air in a room is changed on average 4 times every hour.
so that means the heating system needs to heat the whole room 4 times every hour... keeping it simple...
a HRV system uses already heated stale air in the house to preheat fresh air coming into the house...

so just say a HRV system is 80% efficient... that means in 1 hour the heating system only needs to heat 20% of the room... so it would take 5 hours before the whole room is heated with complete new heat from the heating system....(5 x 0.2)
now if passive vents were used that 5 hour period the heating system would need to heat the whole room 20 times (5 x 4)

so using SBs example of gas above.... if it costs 20c per hour to heat a room with passive vents, it only costs 1c per hour to heat a room with a HRV system.

Thats very simplified and theres probably some who will question it, but thats the way i see it.

Syd, can you pm me the details of the HRV system for 4k please

Regards
Slates

sydthebeat

Mellor wrote: »

What are A rated windows?
I've heard this before, and had a feeling that it was a sales pitch from a guy who had no BER knowledge.
Hopefully, its an EU designation. And there are some sort of limits that must be met, but i'm not 100% on that.

mellor....

http://www.bfrc.org/

BFRC Ltd is the operation of a UK national rating system for the thermal performance of fenestration products.

Slig

If you are just looking for a good rating without the practical advantages (eg if you are just looking to sell a house and want a sales pitch) then there are plenty of Assessors out there.
I personally believe that you should look at what you can do to improve the house for yourself and then maybe get a rating done.

derickmc

A bit of both. I am aware of some areas where the BER doesn't quiet cover may not show the full picture. i.e. excellent windows but poorly fitted more than cancelling out their positive effect.

My plan is to rent out this house and that is why I am focusing so much on its energy rating. I do hope to use it as a selling point but I also want the house to be done right from day one and not to be rerenovating down the line.

To a large extent targeting a high BER should do hand in hand with improving the houses energy performance.

topcatcbr

Derick I have done a number of these and it is very hard to get a second hand home to an A rating. B rating is definity possible a simple way to explain is. Are you prepared to excavate your ground floor just to install insulation there? This will give you some example of the lengths and expence required. I dont want to scare you off though and admire your commitment. My advise for what its worth is to employ a BER assessor who can also design the required changes to the property. Ask them for what you require and what experience they have in doing this. Generally speaking an engineer Architect/Tech or building surveyor (in no particular order)would be suitable.

Regards.

Pm me if you want someones phone no as i know someone suitable in your area.

dahayeser

I am my house too it is an old 1920's house. Surprisingly given the era it was built the walls a less than a foot thick, it is single leaf obviously.

I started am insulation job recently. My main priority was to sound proof it a bit as we could hear everything from the neighbours house so I battoned the party wall and put simi rigid slabs of rockwool (fibreglass) between the battons, I then screwed a sheet of 1/2" OSB (wood) on to that (to give a grip for pictures etc before finishing with a 1/2" slab.

It worked wonders on the sound proofing and I continued this around the inside of an external wall fully insulate the room. This has made a big difference when heating and maintaining heat in the room however from reading some of the earlier posts I am wondering if this construction is likely to sweat and cause me problems down the line ..

I have only one wall done at the moment. Would anyone in the know be able to post the best method / combination of materials in their opinion of insulating an internal wall on the inside.

Just a comment on the A rated windows and their relevance or lack of to the BER rating. I read it is impossible to get an A rated shash window because of the way they close, they don't have a flap that seals in over the opening when closed like most regular windows.

The BER rating doesn't take in this window rating in to account. The BER just takes into account the window area, glazing type, age, frame type, if low-e glass and orientation and does its own calculations. So a Sash window might score as highly for you in the BER as another higher rated window.

Slig

dahayeser wrote: »

I am my house too it is an old 1920's house. Surprisingly given the era it was built the walls a less than a foot thick, it is single leaf obviously.

I started am insulation job recently. My main priority was to sound proof it a bit as we could hear everything from the neighbours house so I battoned the party wall and put simi rigid slabs of rockwool (fibreglass) between the battons, I then screwed a sheet of 1/2" OSB (wood) on to that (to give a grip for pictures etc before finishing with a 1/2" slab.

It worked wonders on the sound proofing and I continued this around the inside of an external wall fully insulate the room. This has made a big difference when heating and maintaining heat in the room however from reading some of the earlier posts I am wondering if this construction is likely to sweat and cause me problems down the line ..

I have only one wall done at the moment. Would anyone in the know be able to post the best method / combination of materials in their opinion of insulating an internal wall on the inside.

Just a comment on the A rated windows and their relevance or lack of to the BER rating. I read it is impossible to get an A rated shash window because of the way they close, they don't have a flap that seals in over the opening when closed like most regular windows.

The BER rating doesn't take in this window rating in to account. The BER just takes into account the window area, glazing type, age, frame type, if low-e glass and orientation and does its own calculations. So a Sash window might score as highly for you in the BER as another higher rated window.

The picture hanging idea is great:D. I dont know if it would sweat or not but I like your thinking. The other way would be double plasterboard slabs but I dont know about the expense.

sinnerboy

I would take care not to vapour seal your external walls . ( you said internal - but i assume you meant external ) Those old walls will at times need to release vapour back into the building - don't trap it . Use plasterboard with either siga/intello or vario membrane behind it and over the insulation . Those membranes will help get you air tightness whilst remaining vapour open

if you want racking strength ( good fixings base ) use either Fermacell or Sasmox

dahayeser

Excellent thanks! Out of interest would the Fermacell or Sasmox on an external wall put me back to square one though trapping the vapour?

derickmc wrote: »

On the dry lining are you sure the assessment factors in the break in insulation where an internal wall intersects the insulation on an external wall? I was under the impression that the BER system would not factor this in and it would count as a fully insulated wall ..

Jumping back to something dry lining / BER issue mentioned on the thread earlier. My understanding of the above is the same as your's Derick.

Can anyone else throw any light on this ?

Slig

dahayeser wrote: »

Excellent thanks! Out of interest would the Fermacell or Sasmox on an external wall put me back to square one though trapping the vapour?



Jumping back to something dry lining / BER issue mentioned on the thread earlier. My understanding of the above is the same as your's Derick.

Can anyone else throw any light on this ?

I cant speak for the Existing buildings course but with the original DEAP this was up to the discression of the assessor. It would be very easy for an assessor just to use the u-value of the dry-lined wall if they werent very particular.

sinnerboy

Fermacell and Samox will breath

Slig wrote: »

I cant speak for the Existing buildings course but with the original DEAP this was up to the discression of the assessor. It would be very easy for an assessor just to use the u-value of the dry-lined wall if they werent very particular.

Not correct - DEAP - thermal bridging . If an assesor , in the case of new or existing , does not have EVIDENCE of , or a "sign off" by a certifying architect or similar professional , that

for 2005 regs - homebond right on the site , or UK accredited details have been implemented - then a "y-factor" of 0.15 factor MUST BE APPLIED . In other words the uninsulated parts are taken into account

http://www.planningportal.gov.uk/england/professionals/en/1115314255826.html

for 2007 regs - similar to above except sign off is to Irish Acceptable details

http://www.environ.ie/en/TGD/

Monti Redux

dahayeser wrote: »

Just a comment on the A rated windows and their relevance or lack of to the BER rating. I read it is impossible to get an A rated shash window because of the way they close, they don't have a flap that seals in over the opening when closed like most regular windows.

The BER rating doesn't take in this window rating in to account. The BER just takes into account the window area, glazing type, age, frame type, if low-e glass and orientation and does its own calculations. So a Sash window might score as highly for you in the BER as another higher rated window.

The BFRC doesn’t certify ’sliding sash’ windows. The certification relates to a specificed form factor and size but that hasn’t stopped several companies making all sorts of claims. At Plan Expo recently the sales reps on one stand were claiming that their French casement and a single casement were ‘A’ rated. This is rubbish. They had one particular window rated but they were claiming it applied to just about everything they made.

At the Building Exhibition another company was promoting an ‘A’ rated windows in an even more outrageous fashion (some of you will know what I’m referring to) but the blokes on the stand had never even heard of window energy rating. Just because a window has a low u-value does not mean it is ‘A’ rated.

Incidentally the whole scheme is aimed at the domestic replacement market and the weighting that generates the energy rating is questionable to put it mildly. The data on the label only relates to the specific window size that was tested so its fairly useless for any sort of BER or PHPP analysis.

Monti

Carawaystick

sinnerboy wrote: »

If you can afford it rip out your timber floor including joists under and hack up your concrete floor and insert a radon barrier , min 200 exp poly insulation and new 150 concrete slab over .

Surely getting a radon detector in for 3 months to see if radon is a problem would be less hassle than putting a barrier down blindly?

sinnerboy

Just putting my walking cane to one side .....

The reason to hack up the floors , if budget allows , is to provide insulation firstly , radon barrier is "while your at it "

RKQ

Carawaystick wrote: »

Surely getting a radon detector in for 3 months to see if radon is a problem would be less hassle than putting a barrier down blindly?

A radon barrier is also a Damp-proof-membrane, preventing rising damp penetrating the building - very important for a healthy home.

The installation of insulation and a d.m.p would be well worth considering.