Air tightness in cavity build and HRV

dos29

Greetings all,
I'm looking for some advice on the above mentioned. I'm currently building a story and a half with 50mm insulated plasterboard, 100mm block, 150mm cavity(full filled with bead), 100mm block, and regular plaster. I'm also planning on fitting a HRV in the house.
So I'm wondering what are the general precautions taken to airtight this type of build.
Also, can people who have installed HRV units let me know, by PM if necessary, what company they have used and if it lives up to expectation, noise wise as well as performance.
Lastly, I know its asking a lot, but... if there is anyone out there who's not too far from the cork area who has a HRV they are happy with, and wouldn't mind a stranger having a look, it would be an absolutely huge help:o.
My other half doesn't want to get one until she see's/hear's one in action, and I know absolutely nobody that has one yet.

Thanks in advance for help on any part of this.
I know theres a lot in there, but I figured I'd kill it all with one thread instead of multiples.

beyondpassive

I'd recommend 220 to 250mm of full fill wide cavity, with a thermally broken inner leaf. Dry lining with composite board is nonsence, all it does is keep your inner leaf cold, thus contributing nothing to thermas inertia and allowing it get below dew point. As its storey and a half, the eaves and and sloping section of the roof are critical. The 'soldsold' specification is prob the best place to start. So 60mm softboard liner isout formost budgets go for 22. rafter and battens to make a 250mm void between rafters filled with 60kg/m3 celluklose with 15mm osb inside as vaopur control and airtight layer. with insulated services cavity inside. This is necessary to keep the comfort levels especially during summer overheating on days like these. This spec has been proven empirically and anecdotaly to offer the best levels of performance at conventional build costs. Anything less is a false economy.

The key word s in achieving airtightness iare care and vigulance, there is a lot of effort needed to seal all gaps and equally you need to ensure all trades understand what you are trying to achieve at 1 airchange per hour.

With the HRV, make sure it is designed to suit your house geometry. Solid ducts such as polyethelene with as few bends as possible and minimum use of flexi's. The system should be designed to deliver at least 0.7 airchanges at mid setting. Its best to locate the MHRV inside the thermal envelope, once vibration is managed, you ned to access the filters a lot in the early stages as there is a lot of dust in finished buildings. You also need it to activate the summer bypass for hot weather.

Leadership

Heat Merchants in Cork have a HRV system setup in their branch Togher and you can hear and see that one running.

sas

Not that you shouldn't go see\hear a hrv system insitu, but the noise is more of a side effect of poor design in the pipe layout and absence of noise mufflers at key points afaik.

Basically, you could go to 1 house and think it's a disaster, another and think it's fantastic.

dos29

Thanks for all the replies so far. I'll definately check out Heat Merchants. Which one has it by the way? I see theres 3 in Cork.

the noise is more of a side effect of poor design in the pipe layout and absence of noise mufflers at key points afaik.

I see what your saying. As I said, its more for herself's piece of mind that one needs to be seen in action.
In saying that, I'd still like to hear from anyone who has either positive or negative experience if only to know more about what to pay particular attention to, or which company's get the thumbs up or down. So far, I'm reckoning I'll be going with solid ducting all the way.

Does the attic have to be made airtight for HRV?
I'm planning on having the unit located in the attic, which will only be used for storage. Its just not big enough for anything else.
So my plan was to airtight windows, doors and any service holes etc for ground floor and 1st floor, and the ceiling of the 1st floor.
Leaving the attic space ventilated by eaves.
Seeing as there will be no inlets, outlets or heating in the attic, is there a point in including that in the "envelope"?

As for a larger cavity, I'm using the KISS(keep it simple stupid) principle. The costs of the larger filled cavity combined with risks of mistakes in building and the difference in energy savings from 150mm filled to 220mm filled weighed against the price I'm getting a 150mm built for, just doesn't enthuse me.
This is honestly the first time I've heard

Dry lining with composite board is nonsence

Is this common knowledge?
Again, thanks so far.

chamaid

I agree with the extra wide cavity. Attic doesn't need to be airtight (NB Condensation). HRV is a good job

beyondpassive

dos29 wrote: »

As for a larger cavity, I'm using the KISS(keep it simple stupid) principle. .

I always thought it was the 'keep it stupid, simple.' principle.

imitation

dos29 wrote: »

Greetings all,
I'm looking for some advice on the above mentioned. I'm currently building a story and a half with 50mm insulated plasterboard, 100mm block, 150mm cavity(full filled with bead), 100mm block, and regular plaster. I'm also planning on fitting a HRV in the house.
So I'm wondering what are the general precautions taken to airtight this type of build.
Also, can people who have installed HRV units let me know, by PM if necessary, what company they have used and if it lives up to expectation, noise wise as well as performance.
Lastly, I know its asking a lot, but... if there is anyone out there who's not too far from the cork area who has a HRV they are happy with, and wouldn't mind a stranger having a look, it would be an absolutely huge help:o.
My other half doesn't want to get one until she see's/hear's one in action, and I know absolutely nobody that has one yet.

Thanks in advance for help on any part of this.
I know theres a lot in there, but I figured I'd kill it all with one thread instead of multiples.

The SAP Appendix Q is always worth a visit, the installation guides are quite informative.

http://www.sap-appendixq.org.uk/page.jsp?id=16

I wasnt too impressed with heat merchants hrv setup, its just a box on the wall really, theres not much to see. I have been in a few houses with HRV, its tough to see the immediate benefits of it, as its more of a long term thing with air quality and heating savings. I did visit at a good time, during the cold snap at the start of this year. The houses all felt warm, but the air didnt feel stuffy.

soldsold

I took a trip to UK last wednesday for a HRV training course in Burton-on-trent.

Free course with lunch, 14 euro ryanair flight, 56 pounds hertz car rental, lots of coffee and chocolate brownies, and a gps to get me from birmingham airport to the door of the HRV company - gps is so great!.

The units are very silent, hard to even know they are on in the same room with no pipework attached. However attaching some pipe ducts makes the noise levels rise, so as SAS says abobe - in one house its silent, in another its noisy.

Some general stuff I was informed of:

- Flexible duct is a bad idea as its very inefficient. Stick with solid duct with maybe some flexible near the inlet points.
- White metal circular ceiling supply grids are the same price as white plastic in this company but look much better (less cheap looking).
- Rectangular solid duct 200mm x 60mm performs much the same as 150mm round, as it has the same surface area, and its easier to ship as it folds flat, easier to install as it bends to fit in between mf ceiling metal for example or in a 100mm service duct. Apparently the efficiency was tested independently but I'm still taking this claim that rectangular is as efficient as round with a major pinch of salt. In my case I don't have room in the dropped metal mf ceiling below the concrete slabs for 150mm round so Ive no choice, but Ill be using 150mm round PVC ducts in under the eaves where I have space.
- A minimum of 750mm is needed between the external inlet hole and outlet holes. 2 meters is better.
- The guy running the course (which should have been cancelled as no one else was able to turn up, but because I had the flights booked and am buying two units and ductwork they went ahead with a 1 to 1 course just for me! fair play to them) said the unit in his own house has just about no noise even if turned up full blast, I believed him as he would have made more selling me soundproofing baffles, he said I wont need them.
- The soundproof baffles definitely make a difference, immediately the sound levels dropped a lot when the baffles were attached
- The cooker hood this company supplies has an air wash from the top down around all sides to keep steam from getting out, and is connected to the HRV so the steam is vacuumed away by the HRV unit. The steam/ grease etc goes through a 5 layer grease trap which is dishwasher friendly, all in all I was convinced the HRV ducts wouldn't end up as a bacteria hive if cleaned in the dishwasher once a fortnight, and the hood looked good and very quiet compared to a normal hood.
- Running costs in electricity: 20 euro a year for one unit, I need two so 40 euro a year. Add filters at 35 quid a pop or so, being replaced every 18 months. The filter is just a rectangular fabric/ wool/ spongy thingy that doesnt look like it should cost so much, Im guessing thats the gillette business model, sell the razor cheap and make the ongoing profit on the blades (or in this case, filters). Maybe there is a cheaper source ie a spurious part? Also the main heat recovery unit will get filled with gunk even with changing filters and its a few hundred sterling, every so many years a new one is needed - I have the notes somewhere. And motors/ thermocouples might fail. And the guy suggested the lifespan was maybe 15 years but looking at the plastic its mainly made from Id say an indefinite lifespan once the filters/ motors etc are replaced if they break. My opinion was that lifespan isn't a big issue.
- Efficiency: I questioned the efficiency rating of 90% or so (on the SAP index which I made sure of some time ago) as I guessed the 90% heat recovery was based on perfect inside vs outside temperature conditions, the guy running the course said it is not, you will get around 90% all the time if commissioned properly. The jury is out with me on this one but Im happy if I get 70% plus as the main reason is to allow me to make the house airtight, remove dust from incoming air, less fly's and other bugs as all windows closed as needed, remove pollen and doggy odours/ skin dust as my other half suffes when the dogs are inside too much, reduce draughts, remove smells from cooking/ dogs/ toilets/ smelly guests/ etc, remove moisture from the house so no condensation and finally recover some of the expected heat loss with a crisp, fresh air quality.
- It was suggested to me to use duct tape/ or a white tape I was shown that didn't look a patch on airtightness tape so Ill be sticking with airtightness tape to tape the duct joints, the white tape looked like silage tape.
- The speed control (RF control box) is a thin rectangular control box about 3 inches square and 1/4 inch thick, with a button for level 1,2 and 3 and a 10 minute boost button, its comes with a sticky tape back so you can stick it anywhere and can have a load of them in the house wherever you like. Wired units are also available but you cant control them as easy, apparently the one thats turned up needs to be turned down whereas any of the RF units can turn the speeds up or down.
- Balancing the room feed and extraction depends on the room and the size - eg a kitchen needs 13m3/hour extraction, an en-suite is 6 (dont quote me on these its off the top of my head) and other rooms are based on their size but you balance the flow/ return by opening or closing the center piece of the room feed ceiling unit.

So, having done the course, and assuming my installation goes well, Im thinking of starting to import the units. HRV should be fairly cheap, Irish prices I have seen doesn't show this and it should be possible to have low overheads and supply the units with good advice at UK prices.

Anyway, hope the above is of use, as you might have noticed I havent mentioned the name of the company I'm buying the units off so I stay within the forum charter so PM only please if you want details.

Soldsold

dos29

WOW! You really went to town with that post Soldsold. Fair play to ya, I can't come up with a single question that you haven't covered(yet!;)).
I would love to get the name of the company and maybe rough prices off ya by PM if ya don't mind.
Do they have people in Ireland to install, or is it because they don't that you went over for the course?

imitation

Really nice post soldsold, I`ll be taking notes for my own build

soldsold wrote: »

- The cooker hood this company supplies has an air wash from the top down around all sides to keep steam from getting out, and is connected to the HRV so the steam is vacuumed away by the HRV unit. The steam/ grease etc goes through a 5 layer grease trap which is dishwasher friendly, all in all I was convinced the HRV ducts wouldn't end up as a bacteria hive if cleaned in the dishwasher once a fortnight, and the hood looked good and very quiet compared to a normal hood.

The alternative I have seen to this is a standard external vent for the hood, but it has a valve in it that closes when the hood is turned off. I'm favoring this myself for simplicity, and just to be 100% certain about smells.

- Running costs in electricity: 20 euro a year for one unit, I need two so 40 euro a year. Add filters at 35 quid a pop or so, being replaced every 18 months. The filter is just a rectangular fabric/ wool/ spongy thingy that doesnt look like it should cost so much, Im guessing thats the gillette business model, sell the razor cheap and make the ongoing profit on the blades (or in this case, filters). Maybe there is a cheaper source ie a spurious part? Also the main heat recovery unit will get filled with gunk even with changing filters and its a few hundred sterling, every so many years a new one is needed - I have the notes somewhere. And motors/ thermocouples might fail. And the guy suggested the lifespan was maybe 15 years but looking at the plastic its mainly made from Id say an indefinite lifespan once the filters/ motors etc are replaced if they break. My opinion was that lifespan isn't a big issue.

Running costs seem lower than other HRVs I have seen. 18 months seems longer than the average I have read too. Is it a rotary wheel hrv or the "other type" (I cant remember the name at this stage).

10-15 years sounds about right, although it could be less, considering it will be running 24/7. I think replacement costs should have fallen a fair whack by that stage anyway, as the way things are heading with regs everybody will be using them.

- The speed control (RF control box) is a thin rectangular control box about 3 inches square and 1/4 inch thick, with a button for level 1,2 and 3 and a 10 minute boost button, its comes with a sticky tape back so you can stick it anywhere and can have a load of them in the house wherever you like. Wired units are also available but you cant control them as easy, apparently the one thats turned up needs to be turned down whereas any of the RF units can turn the speeds up or down.

They all seem to do RF units, which is fine until the dog runs off with it or theres no AA battery's left in the house ! The wired system sounds very basic indeed, I'd imagine you could fix which unit controls the speed it with some diy electronics.

Could you kindly PM on me the details.

poregan

Does anyone have details of who in Cork does airtightness work
No necessarily for HRV. The roof is on the house and my next step is insulation, picking up alot of information at the moment, hence the airtightness that i hadn't heard of till 2 months ago

soldsold

imitation wrote: »

1) The alternative I have seen to this is a standard external vent for the hood, but it has a valve in it that closes when the hood is turned off. I'm favoring this myself for simplicity, and just to be 100% certain about smells.

2) Running costs seem lower than other HRVs I have seen.

3) 18 months seems longer than the average I have read too.

4) Is it a rotary wheel hrv

5) I think replacement costs should have fallen a fair whack by that stage anyway, as the way things are heading with regs everybody will be using them.

6) They all seem to do RF units, which is fine until the dog runs off with it or theres no AA battery's left in the house ! The wired system sounds very basic indeed, I'd imagine you could fix which unit controls the speed it with some diy electronics.

7) Could you kindly PM on me the details.

1) The price of the HRV hood vs ordinary hood is probably not huge but of course depends on the amount you would be expecting to pay for an ordinary hood. Winter cooking generates a lot of heat so Id like to keep it, the unit doesnt seem to be hard to fit to the HRV, just add as an extraction point.

2) 17 pounds electricity usage per year is what I was quoted

3) I'll check this, did the post from memory.

4) No, its not a rotating unit. The point was made to me that any extra mechanical stuff in a HRV is an expense to run with possible maintenance breakdown issues.

5) Good point and most likely very true

6) The RF unit ia about 100 pounds more expensive but you can stick the RF controller anywhere its about as thick as a tile and the size of a beer mat. If the batteries did die you could use a different RF controller while waiting for batteries.

7) Will do

cuculainn

soldsold wrote: »

I took a trip to UK last wednesday for a HRV training course in Burton-on-trent.

Free course with lunch, 14 euro ryanair flight, 56 pounds hertz car rental, lots of coffee and chocolate brownies, and a gps to get me from birmingham airport to the door of the HRV company - gps is so great!.

The units are very silent, hard to even know they are on in the same room with no pipework attached. However attaching some pipe ducts makes the noise levels rise, so as SAS says abobe - in one house its silent, in another its noisy.

Some general stuff I was informed of:

- Flexible duct is a bad idea as its very inefficient. Stick with solid duct with maybe some flexible near the inlet points.
- White metal circular ceiling supply grids are the same price as white plastic in this company but look much better (less cheap looking).
- Rectangular solid duct 200mm x 60mm performs much the same as 150mm round, as it has the same surface area, and its easier to ship as it folds flat, easier to install as it bends to fit in between mf ceiling metal for example or in a 100mm service duct. Apparently the efficiency was tested independently but I'm still taking this claim that rectangular is as efficient as round with a major pinch of salt. In my case I don't have room in the dropped metal mf ceiling below the concrete slabs for 150mm round so Ive no choice, but Ill be using 150mm round PVC ducts in under the eaves where I have space.
- A minimum of 750mm is needed between the external inlet hole and outlet holes. 2 meters is better.
- The guy running the course (which should have been cancelled as no one else was able to turn up, but because I had the flights booked and am buying two units and ductwork they went ahead with a 1 to 1 course just for me! fair play to them) said the unit in his own house has just about no noise even if turned up full blast, I believed him as he would have made more selling me soundproofing baffles, he said I wont need them.
- The soundproof baffles definitely make a difference, immediately the sound levels dropped a lot when the baffles were attached
- The cooker hood this company supplies has an air wash from the top down around all sides to keep steam from getting out, and is connected to the HRV so the steam is vacuumed away by the HRV unit. The steam/ grease etc goes through a 5 layer grease trap which is dishwasher friendly, all in all I was convinced the HRV ducts wouldn't end up as a bacteria hive if cleaned in the dishwasher once a fortnight, and the hood looked good and very quiet compared to a normal hood.
- Running costs in electricity: 20 euro a year for one unit, I need two so 40 euro a year. Add filters at 35 quid a pop or so, being replaced every 18 months. The filter is just a rectangular fabric/ wool/ spongy thingy that doesnt look like it should cost so much, Im guessing thats the gillette business model, sell the razor cheap and make the ongoing profit on the blades (or in this case, filters). Maybe there is a cheaper source ie a spurious part? Also the main heat recovery unit will get filled with gunk even with changing filters and its a few hundred sterling, every so many years a new one is needed - I have the notes somewhere. And motors/ thermocouples might fail. And the guy suggested the lifespan was maybe 15 years but looking at the plastic its mainly made from Id say an indefinite lifespan once the filters/ motors etc are replaced if they break. My opinion was that lifespan isn't a big issue.
- Efficiency: I questioned the efficiency rating of 90% or so (on the SAP index which I made sure of some time ago) as I guessed the 90% heat recovery was based on perfect inside vs outside temperature conditions, the guy running the course said it is not, you will get around 90% all the time if commissioned properly. The jury is out with me on this one but Im happy if I get 70% plus as the main reason is to allow me to make the house airtight, remove dust from incoming air, less fly's and other bugs as all windows closed as needed, remove pollen and doggy odours/ skin dust as my other half suffes when the dogs are inside too much, reduce draughts, remove smells from cooking/ dogs/ toilets/ smelly guests/ etc, remove moisture from the house so no condensation and finally recover some of the expected heat loss with a crisp, fresh air quality.
- It was suggested to me to use duct tape/ or a white tape I was shown that didn't look a patch on airtightness tape so Ill be sticking with airtightness tape to tape the duct joints, the white tape looked like silage tape.
- The speed control (RF control box) is a thin rectangular control box about 3 inches square and 1/4 inch thick, with a button for level 1,2 and 3 and a 10 minute boost button, its comes with a sticky tape back so you can stick it anywhere and can have a load of them in the house wherever you like. Wired units are also available but you cant control them as easy, apparently the one thats turned up needs to be turned down whereas any of the RF units can turn the speeds up or down.
- Balancing the room feed and extraction depends on the room and the size - eg a kitchen needs 13m3/hour extraction, an en-suite is 6 (dont quote me on these its off the top of my head) and other rooms are based on their size but you balance the flow/ return by opening or closing the center piece of the room feed ceiling unit.

So, having done the course, and assuming my installation goes well, Im thinking of starting to import the units. HRV should be fairly cheap, Irish prices I have seen doesn't show this and it should be possible to have low overheads and supply the units with good advice at UK prices.

Anyway, hope the above is of use, as you might have noticed I havent mentioned the name of the company I'm buying the units off so I stay within the forum charter so PM only please if you want details.

Soldsold

Hey great information there, can you PM the company you are dealing with?

Thanks

SARAH ANNE

COULD U PLEASE PM ME THE COMPANY U ARE DEALIN WITH THANKS

SARAH ANNE

COULD U PM ME 2 PLS

dos29

After doing some further research, I'm not going to let pride get in the way of doing this house right.
I retract my statement on it not being worth my while to go for a bigger cavity.
I'm now making a 200mm cavity. This way I can get the values I want and have plastered internal walls, which I'm told is even better for air tightness.(someone correct me if im wrong on this, please)
So, if anyone has done/is doing this type of build, I'd appreciate any tips on potential trouble spots, snags.
(The floor is yours beyondpassive )
Thinking about using the kwik fix wall ties. Are these fully certified now and A ok to use? Or can someone suggest an alternative? If anyone has costs of any of these I'd appreciate the info, by PM if necessary.
That is all (for now!).

JB81

Could you PM me too please thanks

creedp

Soldsold I'd appreciate it if you could PM me the details of your HRV supplier please. I'm interested in the cooker hood issue as the people I have spoken to do not recommend connecting the hood to thier systems die to dangers of fire/contamination. All views on this issue welcome

doctorjohn

Just like creedp I am very interested in the cooker hood company you are dealing with. Could you pm me the company details please.
Many thanks

"The cooker hood this company supplies has an air wash from the top down around all sides to keep steam from getting out, and is connected to the HRV so the steam is vacuumed away by the HRV unit. The steam/ grease etc goes through a 5 layer grease trap which is dishwasher friendly, all in all I was convinced the HRV ducts wouldn't end up as a bacteria hive if cleaned in the dishwasher once a fortnight, and the hood looked good and very quiet compared to a normal hood."

Thanks for giving us all this level of detail
Much appreciated

doctorjohn

http://www.tamtech.com/store/dampers,category.asp

Guys,
I have been following the discussion here and on other forums (fora???) about cooker extractor hood being vented into MVHR and am coming to the conclusion that I am going to keep the cooker extractor and tumble dryer ventings separate and put them through the envelope of the house to the exterior and cover with a standard grill. My issue is that these vent covers are anything but airtight and surely if the MVHR generated even a smidgin of negative pressure it would draw air in from these ventings even though they are covered.

Will you have a look at these dampers above and see if you think they are a nonsense or a good idea or if you could suggest something similar this side of the atlantic.

They don't seem extravagant at 15 dollars a pop. I wonder if putting in a few of them in series would be greater benefit.
?
Thanks for considering?

randombar

beyondpassive wrote: »

I'd recommend 220 to 250mm of full fill wide cavity, with a thermally broken inner leaf. Dry lining with composite board is nonsence, all it does is keep your inner leaf cold, thus contributing nothing to thermas inertia and allowing it get below dew point. As its storey and a half, the eaves and and sloping section of the roof are critical. The 'soldsold' specification is prob the best place to start. So 60mm softboard liner isout formost budgets go for 22. rafter and battens to make a 250mm void between rafters filled with 60kg/m3 celluklose with 15mm osb inside as vaopur control and airtight layer. with insulated services cavity inside. This is necessary to keep the comfort levels especially during summer overheating on days like these. This spec has been proven empirically and anecdotaly to offer the best levels of performance at conventional build costs. Anything less is a false economy.

Whoa that info sounds great I just don't know what any of it means

Thermally broken inner leaf??

So you're saying there's no need for the dry lining??

What are you recommending for the battens and roof??

beyondpassive

GaryCocs wrote: »

Whoa that info sounds great I just don't know what any of it means

All the more reason to have a good Technologist, Arch, Eng on board early. basically it means a cost effective way of getting high thermal performance where you have rooms in the roof.

Thermally broken inner leaf??

The standard Irish Builder detail, is to build the inner leaf on an uninsulated rising wall. The result of this is a huge amount of heat loss towards your footpath outside.

So you're saying there's no need for the dry lining??

Drylining fixes this problem to a degree, but its a sticky plaster fix not a solution. The inner leaf of the cavity if kept warm with enough insulation in the cavity or external insulation,can contribute to smoothening out the heating and cooling of your house, we call this thermal inertia or heat capacity (k).

(Generally for every kW which raises the internal air temperature, 7 have to be pumped into the structure. This is usually done every morning and evening to ramp up the heat to compensate for the heat lost. The new approach is to keep this heat sealed in the building. The concrete industry and CIF like to say that their standard cavity has this as thermal mass, which it hasn't because the inner block cant hold anything over about 13 degrees.)

Drylining, is a bit of a cheat in that it allows quicker warm up times, as you are really heating the air only as you have created a lightweight building inside a cold structural shell. Very warm when the heating is on. This causes problems in that the air will heat too quickly without the structure to dampen it. The result is temperatures which fluctuate. The secondary effect of this is to raise humidity which will condense against the cold structure. Dry line if you must, and I have done a few in some situations, just be aware is a half assed approach.

What are you recommending for the battens and roof??

see this Thread. http://www.boards.ie/vbulletin/showthread.php?t=2055809510
Cellulose and softboard regulate temperature in roofs where you can have 60 degrees under the slates during the day, and be exposed to a sky radiant temp of minus -150 degrees. The cellulose acts a a flywheel and you get an out of phase relationship where the decrement delay is about 12 hours. In other words relativly speaking to outside temperature,the roof acts an internal chiller during the day and a radiator at night. This is the approach we're take now, good materials and workmanship, instead of a big boiler running 4 times a day. This results in stable levels of thermal comfort, good for the pocket and more importantly for keeping 'those who may feel the cold', content. happy days.

randombar

beyondpassive wrote: »

All the more reason to have a good Technologist, Arch, Eng on board early. basically it means a cost effective way of getting high thermal performance where you have rooms in the roof.


The standard Irish Builder detail, is to build the inner leaf on an uninsulated rising wall. The result of this is a huge amount of heat loss towards your footpath outside.


Drylining fixes this problem to a degree, but its a sticky plaster fix not a solution. The inner leaf of the cavity if kept warm with enough insulation in the cavity or external insulation,can contribute to smoothening out the heating and cooling of your house, we call this thermal inertia or heat capacity (k).

(Generally for every kW which raises the internal air temperature, 7 have to be pumped into the structure. This is usually done every morning and evening to ramp up the heat to compensate for the heat lost. The new approach is to keep this heat sealed in the building. The concrete industry and CIF like to say that their standard cavity has this as thermal mass, which it hasn't because the inner block cant hold anything over about 13 degrees.)

Drylining, is a bit of a cheat in that it allows quicker warm up times, as you are really heating the air only as you have created a lightweight building inside a cold structural shell. Very warm when the heating is on. This causes problems in that the air will heat too quickly without the structure to dampen it. The result is temperatures which fluctuate. The secondary effect of this is to raise humidity which will condense against the cold structure. Dry line if you must, and I have done a few in some situations, just be aware is a half assed approach.


see this Thread. http://www.boards.ie/vbulletin/showthread.php?t=2055809510
Cellulose and softboard regulate temperature in roofs where you can have 60 degrees under the slates during the day, and be exposed to a sky radiant temp of minus -150 degrees. The cellulose acts a a flywheel and you get an out of phase relationship where the decrement delay is about 12 hours. In other words relativly speaking to outside temperature,the roof acts an internal chiller during the day and a radiator at night. This is the approach we're take now, good materials and workmanship, instead of a big boiler running 4 times a day. This results in stable levels of thermal comfort, good for the pocket and more importantly for keeping 'those who may feel the cold', content. happy days.

Thanks for the reply.

I guess I just hate dry lining, need backing everywhere, can't hang things off anything. Dose.

My insulation spec is below.

http://www.building-ireland.com/2010/07/insulation-spec/

To be honest all of this is new to me, have to do a bit of research!!

beyondpassive

Great word press Website.

I like the bit 'if I was building again', particularly because you're just starting. Can I suggest a section called, 'You don't want to do dat!'. it could be filled with vague rants from exasperated building professionals, who are frustrated by the standards of the construction industry.

You can still build open plan, compliance with planning isn't concearned with internal layouts. You can also make slight external changes and rectify those with an application for alterations to previously approved application, but its always best to do this before you build.

I don't think the 0.023 insulation board you intend using in the roof will perform as modelled, so 'you don't want to do dat.' You made a good fist of the planning drawings but you should get a professional on board to produce fully detailed tender drawing and specifications done, if its not down, its an extra.

It may be well worth bringing wall spec up to a 200 cavity and use quinnlite block on the inner side of the rising wall and first two blocks of the inner leaf. Just run it by your Str Eng. Also are you using a centralised heat recovery ventilation system or just holes in the wall.

randombar

Thanks, let me know if you want to add a few posts to it I can sort you out with a username. The if I was building again actually came from another thread here, I have tidied it up a bit and removed the duplicate content and that but it makes for great reading!!! Sounds like a good section to add all right I've heard that off a few builders all ready "Ya that's good in theory but in reality is a load of ar$e"

RE: My build, ya got the house designed by engineers about 3 years ago when I was only going for planning and not really thinking about actually living in it. Some of the stuff is nuts, a cavity wall above nothing downstairs in one part. A toilet behind the chimney block in another, very poor attention to detail and not really using the aspects of the house the best way either.

Probably going to swap the dining room and the living room, one of the lads was suggesting having the back of the house all open plan but 52 feet of open plan is way too much for my liking!!

Thanks for letting me know about the insulation board. What would you recommend instead?

200 hundred cavity sounds good, would you recommend pumping or boards, the guy I might be getting to build the house swears the boards will go in right.

What's the additional cost of the quinnlite blocks, heard they can be pricey enough.

I reckon holes in the wall and maybe put in the piping for the HRV so easy to add later.

soldsold

Ive been off the boards for a few days, was taking photos at a wedding on Friday and editing all weekend so Ive been busy. I'll get to the PM requests over the next day or so, if I miss anyone please let me know.:)

S

hunter1715

Hi Soldsold,
Read the thread, very interesting and thanks for the details. I would be interested in the contact detials for the HRV supplier and how it performs for you when ever it is installed.

Cheers

Fenor

Hi
Just new to this & trying to research HRV systems for a new build
Solssold would you send me details of the company you bought from in the UK. Did you install this yourself?

moan 77

HI SOLD SOLD,

COULD YOU PLEASE PM ME DETAIL ON THE HRV UNIT AND KITCHEN EXRACTOR UNIT BOUGHT IN DE UK.

Dugsy

Soldsold,

Could you please PM me details as well.

Thanks

daveoc16

Hi All,

Good info from Soldsold. I am currently at floor level with my new build. I've been looking just now at HRV. I've been told that the bungalow i'm building should be sealed at the ceilings by an airtight "mesh". Anyone done this, or have any tips??
I also plan to have a living room and a sitting room with insert stoves or one of them an open fire with baloon to seal the chimney when not in use.
The HRV guy said i should install a 2inch pipe from the outside to each fireplace so supply enough air. Anyone know much about this??
I also had planned on using a 50mm insulated board on interior leaf walls, and have 1 150mm pumped cavity. From what i see here some of ye guys aren't fans of the insulated board. I'm at floor level so don't think i can go changing cavity thickness now!
Does anyone have the insulated board and wish they didn't or vice versa??
I'm going to be using underfloor heating by Air to Water heat pump, so heating will be more or less constant level as opposed to oil , stop start.

selfbuild

Hi All,
I to am interested in the HRV unit used could one of you please pm the details of the unit.

Thanks,

AMG86

I sm interested in the HRV unit used. Can you say how it has performed since it was installed. Did you have any particular problems when installing and commissioning it. Can you please pm the details of the unit.