Passive (or near) House Plans - Comments Please

BarneyMc

I'm in a situation where I'm about to finalise plans but not sure where to place the wood burning stove. I'd like to place it somewhere in the kitchen/dining area that's central in the house (will have to be placed on an external wall also due to internal layout).

Does that mean I'll have to build a chimney where I want the stove OR have the flue climb up the wall on the outside? For the latter does the flue have to extend up to the ridge of the building and if so then how can it be supported? Perhaps a proper chimney is a better option but how will this affect air tightness?

The attached picture shows both options in one go!

BryanF

I don't understand the relevance of the picture, its seems to suggest that the existing chimney is redundant and a new flue is installed out side of it.. I may be wrong here of course:o

as regards air-tightness - if you look around the forum there are several threads regarding 'sealed stoves' / external air supply stoves. this approach is applied to remove issues of air-tightness and issues of draw from the MVHR etc. I've seen them in operation and they work grand

sas

BarneyMc wrote: »

I'm in a situation where I'm about to finalise plans but not sure where to place the wood burning stove. I'd like to place it somewhere in the kitchen/dining area that's central in the house (will have to be placed on an external wall also due to internal layout).

Does that mean I'll have to build a chimney where I want the stove OR have the flue climb up the wall on the outside? For the latter does the flue have to extend up to the ridge of the building and if so then how can it be supported? Perhaps a proper chimney is a better option but how will this affect air tightness?

The attached picture shows both options in one go!

The biggest reason to use a regular chimney versus a metal one is product life, the metal flue will definitely need replacing several times over the life time of a masonry chimney.

If we are talking about a cavity build, I would build a masonry chimney in the same manner as that in the picture. Basically, the chimney is part of the external leaf and fully visible from the outside i.e. the chimney stack is outside the insulated shell.

Then the stove would be connected to it via a flue which travels horizontally from the back of the stove, through the inner leaf, through the insulated cavity and finally connects into the chimney in the outer leaf.

The PHI recommends that chimneys\flues are outside the insulated shell of the house in the manner I've just described.

Hope I described it clearly.

SAS

BarneyMc

Thanks guys. Yes SAS you've hit the nail on the head... that's exactly what I wanted to know. A chimney I need then rather than a flue.

The only other thing I need to know then is how high it needs to go. It will be in a place just like in the image so will it have to continue up to the full height of the ridge of the house?

BryanF

BarneyMc wrote: »

Thanks guys. Yes SAS you've hit the nail on the head... that's exactly what I wanted to know. A chimney I need then rather than a flue.

The only other thing I need to know then is how high it needs to go. It will be in a place just like in the image so will it have to continue up to the full height of the ridge of the house?

see dia 1 in attached doc
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1650,en.pdf

sas

BarneyMc wrote: »

Thanks guys. Yes SAS you've hit the nail on the head... that's exactly what I wanted to know. A chimney I need then rather than a flue.

The only other thing I need to know then is how high it needs to go. It will be in a place just like in the image so will it have to continue up to the full height of the ridge of the house?

Something I forgot to mention earlier.

I believe that once you get underway you would do well to consider one of the chimney systems. The most common one here has a specific block with the socket to receive the horizontal pipe into it. The system also has access doors on the outside of the chimney to allow access for sweeping.

If I was doing this again I'd seriously consider one of these.

BarneyMc

Saw this today in one of the papers. Thought it looked good as a buffer area and might suit my plans (south elevation). Has anyone built one of these 'buffer areas' or think they might be useful? I believe they are constructed outside the building envelope?

Should say that there are sliding doors on the main building wall so it can be shut off in cold weather and at night, etc.

BryanF

BarneyMc wrote: »

Saw this today in one of the papers. Thought it looked good as a buffer area and might suit my plans (south elevation). Has anyone built one of these 'buffer areas' or think they might be useful? I believe they are constructed outside the building envelope?

Should say that there are sliding doors on the main building wall so it can be shut off in cold weather and at night, etc.

I very found of this approach , i've seen this used outside of the thermal envolpe as you suggest - their usefulness imo depend alot on whether they will be a usable space.
the winter-garden/sun-room requirement has changed as the cost of glazing and our ability to have more constant internal temps with MVHR/ good air-tightness as standard (there are still some crazy people out there who build traditional conservatories and then place radiators in them!!). The design you suggest does require some consideration in the passive house modelling, but this may come down to how its described in the calculation. Depending on the situation, careful consideration is necessary to give thermal separation, thermal mass, shading and risk of overheating (or cooling).

just do it

BarneyMc wrote: »

Saw this today in one of the papers. Thought it looked good as a buffer area and might suit my plans (south elevation). Has anyone built one of these 'buffer areas' or think they might be useful? I believe they are constructed outside the building envelope?

Should say that there are sliding doors on the main building wall so it can be shut off in cold weather and at night, etc.

All depends on budget! I'd say if you like it submit the plans with it, model your house up in PHPP with and without it. Build it, or alternatively without it and in such a way that you can add it on in the future should funds allow. Anyway food for thought;)

BarneyMc

Finalising plans this weekend and having second thoughts about some of the south facing floor to ceiling windows. I know they give a great view to the outside but are there any installation issues regarding airtightness (where they meet the floor)? If so then would they be better sitting a block or 2 off the ground?

sas

BarneyMc wrote: »

Finalising plans this weekend and having second thoughts about some of the south facing floor to ceiling windows. I know they give a great view to the outside but are there any installation issues regarding airtightness (where they meet the floor)? If so then would they be better sitting a block or 2 off the ground?

I dont think you've anything to be concerned with. Several of mine go to the floor. You simply tape onto the floor slab.

What was your concern?

BarneyMc

sas wrote: »

I dont think you've anything to be concerned with. Several of mine go to the floor. You simply tape onto the floor slab.

What was your concern?

Just thought it might be a difficult area to detail but thanks, look like it should be ok