Some random questions

JohnBoy

We're at the early stages of designing our home.

we have outline for a single story but we're trying to put together our requirements/ideas for the house we want.

this is intended as a house for life as it will be built on my girlfriends farm.

I'm just gonna have this thread here if ye dont mind where i'll post my random questions as i think of em.

Right now there's no construction method decided, we want to be energy efficient without being too adventurous.

1) velux windows: in terms of energy efficiency are we doomed from the start? and can velux windows satisfy fire escape requirements in the building regs?

2) precast concrete hollow core floors: how do they compare in thickness to traditional wooden joists? (how long is a piece of string eh? lets say a 30 foot span?

3) basements: considering a basement for utility room, hot press, storage, home gym type stuff. Apart from the requirement that the basement has a seperate stairs for access what are the other issues? site is elevated, on a slight slope and well drained so i doubt the water table is an issue.

I'll probably have more questions as time goes on, but i figured i'll keep em together for now rather than spamming the whole forum.

archtech

There are velux windows which meets the requirements for means of escape. , you can also get a velux solar panel system which can be integrated into the roof with the velux windows.

I would be trying to a void constructing a basement if i could, there's a lot additional of cost associated with same, however positioning of the dwelling on the site may lead itself to a basement/ partial basement.

Mellor

1. It depends on which windoe is used and how large it is and how many. The best velux window in terms of energy is probably the sun tubes.
   As for escape, velux windows do comply with escape, not all of them, but there are plenty within limits of Part B.
2. Holowcore floors are about half the size of timber joist floors. Often, people who go for hollowcore floors go for block walls upstairs, which will increase floor.
3. Other issues with a basements are cost, keeping water out (regardless of water table) and lighting.

JohnBoy

@archtech: i like the idea of the solar panels integrating into the roof with the velux windows, could probably be done very nicely to give a fairly continuous looking surface

@mellor: yeah i guess the sun tubes wouldnt be too bad (relative to actual windows) from an energy perspective, but not at all a fan visually.good to know on the hollowcore floors, not sure i see the benefit of block walls upstairs, i've lived with both types and i'm not sure there's much benefit.

no clue how realistic the basement idea is, we'd have to get serious costings done on it to see if its viable.

below is a list of our other ideas/plans

4 bedrooms, simple plain white exterior
Large kitchen - dining room
Living room
Sitting room
bathroom
Master bedroom with full size en suite
2 bedrooms with a shared en suite
1 bedroom with no en suite
Roof designed with attic conversion in mind (if not already in use), space in hall for stairs

Separate garage

sydthebeat

by that brief, you would have a large ground floor area (possible 2500 sq ft.. thats a modest appraisal) and, depending on the design, a possible 2/3 of that again as attic area available for conversion... ie 1670 sq ft.. so you could end up with a 4170 sq ft dwelling... which is very large.

If you are confident on recieving planning for a ridge line high enough to allow for an attic conversion, would you not plan for some of the bedrooms in the attic space initially to keep costs down. Cost per sq ft in the attic space can be as low as 30% of that at ground floor level.??

Mellor

JohnBoy wrote: »

@mellor: yeah i guess the sun tubes wouldnt be too bad (relative to actual windows) from an energy perspective, but not at all a fan visually.good to know on the hollowcore floors, not sure i see the benefit of block walls upstairs, i've lived with both types and i'm not sure there's much benefit.

Have you seen the velux ones, they are generall one of the better ones. Sit flat on the roof, not like a bubble on top of it.

JohnBoy

2500 sqft????? yikes, how big is a bedroom these days

we currently have 4 bedrooms with 1 ensuite, utility, living room, kitchen/dining, sitting room and bathroom in 1100.

we were moreso targeting 16-1800

if, and thats the big question, if, we could get the ridge high enough then probably the master bed and bathroom would go upstairs.

whats the story with converting an upstairs for purposes other than bedrooms? are the regs as tight? actually what section of the building regs cover attics? are the regs readable?

I want to be as fully armed and informed as possible before we go back to the architect.

JohnBoy

in response to my own question

the building regs dealing with ceiling height
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1647,en.pdf

seems very readable to me.

page 8 gives a clear "suggestion" for attic room ceiling heights.

8 feet.

Mellor

2400 is standard min height for all domestic rooms.
Depending in pitch this will affect the ridge height. The area B not less that Area A/2 diagram should help you get rough idea

JohnBoy

yeah, does indeed, i reckon 2.1m would make life much easier for an attic ceiling height.

especially with the amount of insulation involved either robbing ceiling height or adding ridge height.

hmmm.

will have to spend some time with the olde tech drawing kit at the weekend and see whats feasible.

is there a standard/maximum ridge height for single story houses? guessing not

JohnBoy

More Questions.

building systems: at this early stage we're leaning towards conventional (well its becoming conventional) timberframe with block skin. I've not seen enough of any system that involves external insulation to make me like it. I'm looking at a 60+ year lifespan for this building (hoping to live for a while yet) and i'm just not confident in the weathering of these systems. i know concrete is bad mkayyy but its also pretty good at keeping the weather out imho.


I was asking about hollowcore slabs, can these be used in a timberframe construction? or are they too heavy to be carried on the timberwork? my interest in them lies purely in their thinness, every little helps in getting headroom upstairs while keeping the ridge as low as possible.

Whats the story with local need when going from outline to full planning? we have outline so does that mean that the planning process will relate only to the house or will we come under scrutiny as well?

archtech

Using hollowcore slabs in timber may be achievable (almost anything is) however how cost effective it it could be another story. Have you considered using steel frame construction? Similar principal of construction as timber frame.

You're first floor thickness won't be much less if you use concrete slabs to timber. Typically the wideslab concrete floors have an overall thickness of between 200-225mm. The floor thickness is dependent on the floor spans. You could consider using thicker floor joists(75mm) rather than the deeper . However it the thicker ones are more expensive as far as I know.

Another solution would be use a shallower floor plan which would help reduce the overall building height.

Local need will need to be addressed at "permission consequent on grant of outline permission" stage, if it is applicable to the site.

sinnerboy

JohnBoy wrote: »

More Questions.

building systems: at this early stage we're leaning towards conventional (well its becoming conventional) timberframe with block skin. I've not seen enough of any system that involves external insulation to make me like it. I'm looking at a 60+ year lifespan for this building (hoping to live for a while yet) and i'm just not confident in the weathering of these systems. i know concrete is bad mkayyy but its also pretty good at keeping the weather out imho.

have you considered this ( no i have not used it myself ) . it has a conc facing

http://www.m2ireland.com/

check out the cute "youtube" type demo ....

JohnBoy

in english please archtech

my girlfriend has outline planning in her name, and the planning app will be going through in her name. will she still have to establish local need given that the outline is in her own name?

shouldnt be too hard for her to do i'd imagine but still an additional hassle.

I'm not a fan of steel building systems, what little i've seen of them seem to use quite light gauge steel in their construction, which if the galvanise ever corrodes will rust through in a flash, plus i'm just not sure i'd trust the average tradesman to not start drilling holes through it, hence making breaks in the galvanise. I want to use a system that leaves me feeling confident in its lifespan.

@sinnerboy, i've not seen that before, although it's still just a plastered insulation system is it not. whats the differnence between sprayed on concrete and troweled on cement render?

cant watch the demo on this connection so maybe i'm missing something, i'll check it out tomorrow when i've got bb again

cheers. john

muffler

JohnBoy - if you have planning questions then please post them in the "Planning Issues" sticky on the front page. Cheers

archtech

shouldnt be too hard for her to do i'd imagine but still an additional hassle.

You know that it has to be addressed, so just do it... if permission was refused because the local need wasn't addressed and you had to re-apply then that would be an additional hassle ! Its as easy to do the thing right the first time.

I'm not a fan of steel building systems, what little i've seen of them seem to use quite light gauge steel in their construction, which if the galvanise ever corrodes will rust through in a flash, plus i'm just not sure i'd trust the average tradesman to not start drilling holes through it, hence making breaks in the galvanise

And timber isn't prone to rot or bad workmanship... Any system of construction is only as good as the care and detail used in constructing it.

I want to use a system that leaves me feeling confident in its lifespan.

I suggest that you should consider using some form of concrete construction in that case be it traditional concrete block or possibly a precast system. The bulk of timber frame construction in Ireland has been done in the last 15 years of so, hardly what you would call a lifetime of testing.

And finally what didn't you understand

JohnBoy

archtech wrote: »

Local need will need to be addressed at "permission consequent on grant of outline permission" stage, if it is applicable to the site.

Just that last line

good point about just doing the local need stuff regardless, better safe than sorry.

also a good point that any system is only as good as the man using it. do you have any particular steel systems you'd suggest we should look at?

personally, and this is not really based on anything other than gut feeling, but to me the current tiberframe with block skin while its only in use for 15 years seems like a good concept. but as you say if the detailing is wrong then its wrong, simple as that.



@sinnerboy, thats an interesting system alright, one to investigate further.

sydthebeat

JohnBoy wrote: »

Just that last line

good point about just doing the local need stuff regardless, better safe than sorry.

also a good point that any system is only as good as the man using it. do you have any particular steel systems you'd suggest we should look at?

personally, and this is not really based on anything other than gut feeling, but to me the current tiberframe with block skin while its only in use for 15 years seems like a good concept. but as you say if the detailing is wrong then its wrong, simple as that.



@sinnerboy, thats an interesting system alright, one to investigate further.

They have been using systems like this in canada and europe for over 80 years

Mellor

and some of them failed miserable, resulting it terrible problems with the building. This was due to the fact that a german style system was built in a canada (i think). the different climate combined with slightly different building style resulted in a horrible failure of the system

sydthebeat

The systems that failed were one that didnt use a vented cavity with a block outer leaf. They were simply rendered over timber frames, tended to be high rise in many situations, causing non breathable construction and thus compromise of the structural system..... almost collapsed the whole canadian building industry. Their version of HOMEBOND had to go out of business because of it... as far as i remember. Those mistakes have not to be made again, thus the rigorous testing in ireland in order to achieve the IAB cert.

ardara1

sydthebeat wrote: »

The systems that failed were one that didnt use a vented cavity with a block outer leaf. They were simply rendered over timber frames, tended to be high rise in many situations, causing non breathable construction and thus compromise of the structural system..... almost collapsed the whole canadian building industry. Their version of HOMEBOND had to go out of business because of it... as far as i remember. Those mistakes have not to be made again, thus the rigorous testing in ireland in order to achieve the IAB cert.

Investigations carried out on performance failures of housing construction in British Columbia through the 1980s and 1990s, known as the ‘Leaky Condo Syndrome’, by the Canadian Mortgage and Housing Corporation (CMHC) of 46 buildings of various construction types, of which 37 were reported as having problems, concluded that exterior water penetration was the principal cause for failure. The survey also assessed the cost of repairing problems, the types of wall construction details and statistical analysis of wall details and various building features such as window openings, roofs and flashing details.

The fundamental observation is that nearly all the problem categories relate to interface details and penetrations rather than the basic construction of the wall.
Almost
25% of problems were related to windows;
17% to decks, balconies and exterior walkways; and it was usually the
lack of good design and/or construction of joints that precipitated the reported problems.
The largest single problem area occurred at saddle joints of balconies with surrounding walls where 22 instances of failure were recorded.

Mellor

Ardara is right, the problems were relating to junctions. But the problem at the details, not being properly designed for the variation in construction.
The buildings were built in a method that worked in other countries. When it was brought over the builders made slight changes to be inkeeping with the venacular. I heard one of these was the issue of tax on buildings. In BC tax is based on "roofprint", so the soffit is kept as small as possible to keep tax down, sometimes the soffits were almost non existant, this caused water ingres.

The details of the problems are irrelevant. It was an example. But it highlights the fact that construction isn't universal. The same building system has used built in ireland without problem (I imagine we know who there are, so no need to mention them). because it was detailed correct it appears to work, but not every system is guarented to be ok.

nikki 122

we built our house 2 years ago and i no a thing or 2 about it..... if i were u id go for the fire windows they're safe and nice ... go 4 concrete its more reliable.... basement wud be so much neater than a utility room but bare in mind if u get flooded ur screwed unless u use silicone all around the house where the path and the walls meet!!!

Mellor

nikki 122 wrote: »

basement wud be so much neater than a utility room but bare in mind if u get flooded ur screwed unless u use silicone all around the house where the path and the walls meet!!!

Silicone there will have zero affect on preventing a flood.
If there is a flood, water will be under the path, over the path, under and over the silicone. It won't stop any water. silicone seals between two water proof objects as a joint were it isnt water-tight. The path and walls are not water tight so the silicone will do nothing.

nikki 122

Mellor wrote: »

Silicone there will have zero affect on preventing a flood.
If there is a flood, water will be under the path, over the path, under and over the silicone. It won't stop any water. silicone seals between two water proof objects as a joint were it isnt water-tight. The path and walls are not water tight so the silicone will do nothing.

I beg to differ as I live in a place that gets frequent floods, the contractor told us to use silicone and it works for us ... granted we do not have a basement.

JohnBoy

i seem to have opened multiple cans of worms.....

sinnerboy

go fishing in flood waters with them ....:D

nikki 122

no you havent some people just think they know everything.... arrogance is not an attractive aspect MELLOR!!!!

muffler

nikki 122 wrote: »

no you havent some people just think they know everything.... arrogance is not an attractive aspect MELLOR!!!!

Maybe you would adhere to that yourself.

Any more of this off topic posting and sniping and you're gonna find yourself outa here.

ardara1

I'll been in touch with Ken Livingstone office in London, They've called a halt to the enlargement of the Thames Barrier, they've sent a bloke down to Jewsons for 6 tubes of silicone sealant.:o

sinnerboy

ardara1 wrote: »

I'll been in touch with Ken Livingstone office in London, They've called a halt to the enlargement of the Thames Barrier, they've sent a bloke down to Jewsons for 6 tubes of silicone sealant.:o

Great newts ( geddit ? ? ) NEWTS !

Siobhan12

archtech wrote: »

Using hollowcore slabs in timber may be achievable (almost anything is) however how cost effective it it could be another story.

We're in the process of building and put a ducon slab first floor in, we're going direct labour and used various people for the different parts of the process. Cost was a lot more than we or our engineer envisaged, approx 10K for labour and materials.
2800sqt house - worth doing though for the sound proofing factor.
It takes a couple of weeks too.

Mellor

nikki 122 wrote: »

I beg to differ as I live in a place that gets frequent floods, the contractor told us to use silicone and it works for us ... granted we do not have a basement.

Did you believe everything that your contractor told you.
Its nothing to do with arrogance, its common sense. All advice and posting here is civil, stick to this in future.

JohnBoy

ok, can ye take ye're catfight elsewhere please(hardly qualifies as bitchfighting)

Need to talk to the architecht again about the attic, but if its convertable then the basement idea is completely out, but if its not then it'll still be considered.

nearly ready for another meeting with the architect i reckon.

JohnBoy

Quick HRV question.

as i understand it the HRV is bascially a heat exchanger pulling warm air out and passing it's heat into the cool air coming in.

what about rooms where you would traditionally have extractors? ie bathrooms and kitchens.

does the hrv act as the extractor or do you still have an extractor hood over the cooker?

sinnerboy

air is removed from bathrooms and kitchen ( including extract ) and supplied to other spaces . don't install if

you want an open fire
you don't achieve an very air tight building

JohnBoy

JohnBoy wrote: »

does the hrv act as the extractor or do you still have an extractor hood over the cooker?

Not a good idea to connect the cooker hood to a HRV system, the heat exchanger would get clogged up.
I wanted to do this but the company who did my system didn't recommend it, as for the cooker hood I initially tried recirculating the air, but was forced to install a duct to the outside.

I wanted so try & save the warm air.

MickLimk

sinnerboy wrote: »

air is removed from bathrooms and kitchen ( including extract ) and supplied to other spaces . don't install if

you want an open fire
you don't achieve an very air tight building

Not sure about that. Been doing a bit of research on different models/manufacturers recently and some state that extractor hood should still vent externally. [already mentioned above]

As a matter of interest why do you rule out open fires with a HRV??

sinnerboy

Depends on model selected . Some can connect kitchen extract , I believed all . Thanks for correcting me dolanbaker

Was told today a tale by a HRV supplier . Client wanted HRV + open fire .

Because HRV relies on sealed internal environment to function properly , client was advised against , but did it anyway .

Client would turn off HRV when using fire and would block fire with damper when using HRV .

So client goes away for weekend . Forgets to block fire and leaves HRV on .... and returns to find soot has been dragged around house - decorations ruined .

MickLimk

sinnerboy wrote: »

Was told today a tale by a HRV supplier . Client wanted HRV + open fire .

Because HRV relies on sealed internal environment to function properly , client was advised against , but did it anyway .

Client would turn off HRV when using fire and would block fire with damper when using HRV .

So client goes away for weekend . Forgets to block fire and leaves HRV on .... and returns to find soot has been dragged around house - decorations ruined .

Don't doubt you but it sounds odd. I was under the impression that HRVs worked on a balanced system. They insert as much fresh air as stale air that they exhaust.

If it was sucking air down the chimney, then there may have been an issue with the install or ventilation within/between the rooms? Any idea if this system had only a single feed point for warmed fresh air into the house or was each room fitted with it's own extract and feed?

Apologies for hijacking the thread JohnBoy, but interested in the HRV as an option for my house that has open fires...

Thanks,
Mick

Mellor

It does work on a balence system. Negitive pressure draws in fresh air to replace the stale ait extracted. This pass through the heat exchange. But the exchanger obvious imparts some resistance. Air will be drawn in by the path of least resistance* (see below) until total volume is replaced. With an open fire, there is a 200mm path with a very low resistance, bypassing the heat exchange. Possibably more air too as the amount of air removed is linked to the resistance.


A simple test to show/prove the least resistance path of air havng priority. Next time you are in a restaurant/pub or any where that serves drinks with straws. Take a drink and two straws, put one inside the glass, and one outside. Hold the straws together and try to drink through both together. The one outside the glass represents the flue, the one inside represents the heat exchange. You can pinch the "flue" straw to show the affect a baffle has.

JohnBoy

no probs on the hijack, i'm learning stuff here too.

Not planning an open fire but definitely hoping for a wood burning stove.

Now by my understanding with hrv, or even best practice on energy efficiency this should be fed fresh air from outside.

are the traditional "stanley style" four legged stoves available with external air feeds or would one be looking at a different style unit?

these are minor details but herself likes to think about the details too

Some systems are extract only or have only a fan on the exhaust part of the system.

In my sytem there are air inlets in the "living" areas & extraction in the "wet" areas & air si moved around the house, there are two fans, one on each exhaust & inlet ducts.

JohnBoy

Block and Beam floors......

Whats the story? tommy walshes eco house was on at the weekend and he was using them. whats the pros and cons of this floor type versus a standard floor poured between the walls or a raft?

sydthebeat

JohnBoy wrote: »

Block and Beam floors......

Whats the story? tommy walshes eco house was on at the weekend and he was using them. whats the pros and cons of this floor type versus a standard floor poured between the walls or a raft?

block and beam are generally used on ground floors where there is a large build up of hardcore under, thus increasing the risk of subsidence of a normal poured floor.
They are required by homebond wherever the hardcore depth exceeds 900mm.

use a standard pour where applicable.