Passive

kryan1

Is it possible to create a passive house from an existing house if you are thinking of renovating the existing house.
I have an old ish cottage and i intend on doing an extension. Now the wall are stone and have been dry line YEARS ago, so at the moment they are more than a half a meter thick. So i was thinking of demolising the wall to the front of the house and rebuild it and put in a good amount of insulation, and good windows. I would also knock both gable ends one side as i want to extend the room at that end, and the other side as i wish to add a sunroom and this would really open the house up to the light that would be at that side of the house. the rear wall is actually an internal wall as there was an extension build there around 10 years ago so i would leave this.
So i was reading up on passives houses and i have not seen anything much on existing houses that have been converted, so that is why i ask the question. any advice would be appreciated.
many thanks
Kevin

Outkast_IRE

yes it has been done , but the only way you will manage it without the proper training and knowledge is by getting an architect and possibly a engineer , you really need plans if your aiming for that standard and you need everyone involved in the project to be on the ball .
This website has some Frequently asked question on the whole passive retrofit idea. http://www.mosart.ie/passive-house/retrofit-passive-house.html

it is an architect firms website but the questions are handy ones to read over and there is case studies where they did retrofit. well worth a read

randofmact

Hi Kevin,

A passive house should really be designed from the ground up, it would be quite difficult and impracticle to try to achieve this on an existing cottage.

The straight forward items for passive house can be seperated into 4 catagories, insulation, level of air-tightness, passive heat gains and HRV systems. These should be complimented by renewable energy source(s) to stay in keeping with passive 'philosophy'.

The insulation and air-tighness can be achieved with planning and good workmanship. This will cost a lot more than standard construction though, you will be basically trying to achieve U-values in the same region as an A1 rated home, this would meen taking up all floors to insulate properly, as well as the walls and roof. Roof would probably need to be replaced in order to this this also. Airtightness is basically achieved by wrapping the internal face of the external walls and roof of the house with a membrane which will stop cold air leaking into the house and warm air leaking out, giving more control of the heating of the house. Thats the straight forward stuff!

You would also need to have HRV (heat recovery ventilation). In basic terms this transfers heat from the air being extracted from the house and transfers this heat to the air entering the house, thereby you get fresh air without having to fully heat the fresh air. The cost of a typical installation would be 4-5K. If this is a cottage, then the ductwork that you would need to install will all have to be planned carefully to fit around the space requirements you have. Also, to get the passive heat gains you would have to get as much glazing on the southern side of the building as possible, this would mean that any wall you make have left will have to also be butchered to create new opes.

To be honest, you'd be better off demolishing and building again. Also, i would say that to take on a project like this without an architect/engineer and a good builder you would be mad.

Hope this give you some help.

kryan1

randofmact wrote: »

Hi Kevin,

To be honest, you'd be better off demolishing and building again. Also, i would say that to take on a project like this without an architect/engineer and a good builder you would be mad.

Hope this give you some help.

Many thanks for the info. I totally agree and i would not go down this route with out professional help. These are things that i would not dream of doing. many thanks for the advise

kevin

sinnerboy

kryan1 this will be of interest

BryanF

Kryan1,
see this too http://www.passivehouseacademy.com/downloads/Retrofit-Passive-House-Guidlines.pdf
my advice would be by all means attempt to reach the Passive house standard. the PH standard is far ahead and has set its priorities out much better than the BER system. the new build 15kwh/m2 per year is a tough standard and unfortunately the proposed 'easier' to reach retro-fitting standard is not yet agreed by the institute. all that said maybe you should pick your design team first and set out your low energy & layout design requirements, before talking of demolition as there may be solutions allowing for the retention of the existing structure, something the planners may also like to see.

sinnerboy

BryanF wrote: »

Kryan1, the proposed 'easier' to reach retro-fitting standard is

Available since 20th June

Do-more

sinnerboy wrote: »

kryan1 this will be of interest

Lots of good pointers in that article.

IMO if you have an old cottage which lacks a damp proof course then the big issue you need to address is the breathability of your wall structure. If the wall isn't breathable then any moisture from the ground is going to be driven into the house rather than to outside, giving you problems with damp. Selection of insulation materials and renders is a key consideration.

You also need to be very careful with your floors, if there is no DPM in the walls then damp proofing the floors will drive any moisture from below out towards the walls and could again give you problems with damp in the walls.

Take a look at umbrella insulation, a layer of insulation 15cms or so under ground for 5-10metres all around the house. A damp proof membrane can also be incorporated with this (make sure it is falling away from the house) to take away rainfall so that the ground around and under the house remains as dry and warm as possible.

There are of course considerations to be made in regard to all these details, particularly if your old cottage does not have foundations, so it is vital to employ a good Architect or engineer who is familiar with low energy renovation work and who can say what is appropriate for your particular house.

The important consideration is that every element of your renovation is carefully thought out in harmony with the others and won't give rise to other problems down the line.

By all means set passive standards as a target but, especially with a renovation, from a practical point of view I wouldn't get hung up on having to achieve every detail.

There is a law of diminishing returns and the difference in running costs of a "low energy" house may only be €100-€200 a year more than a passive house but the capital cost may be considerably lower. Would you consider it wise for example to spend €10,000 more to achieve passive spec when the saving to do so would be in the order of €200 a year? You need to do your sums wherever alternatives are presented.

tonyward100

kryan1 wrote: »

Is it possible to create a passive house from an existing house if you are thinking of renovating the existing house.
I have an old ish cottage and i intend on doing an extension. Now the wall are stone and have been dry line YEARS ago, so at the moment they are more than a half a meter thick. So i was thinking of demolising the wall to the front of the house and rebuild it and put in a good amount of insulation, and good windows. I would also knock both gable ends one side as i want to extend the room at that end, and the other side as i wish to add a sunroom and this would really open the house up to the light that would be at that side of the house. the rear wall is actually an internal wall as there was an extension build there around 10 years ago so i would leave this.
So i was reading up on passives houses and i have not seen anything much on existing houses that have been converted, so that is why i ask the question. any advice would be appreciated.
many thanks
Kevin

Isover do a range of insulation for retro work. They also run courses.

DOCARCH

Mod Note: That thread is 4 years old! Please do not grave dig old threads.