ventilation in porton block house

wornout

hi
i have recently had a two storey extension built with poroton blocks and insulated externally with paroc glass wool.the house heats up quickly but it actually becomes unbearable even after turning off the heat.i have noticed that there is no vents in the extension,could this be the cause or are there not supposed to be vents in this kind of build? i am getting conflicting answers
everywhere.anybody out there what the situation is in this regard.

thanks

sas

Given that its a fairly unique building method I would have assumed that the builder would be able to advise on this. Or the supervising engineer\architect?

wornout

hi sas
unfortunately my trust in the builder was misplaced and i had to ban him from the site,an architect had a look and said i must have ventilation in the extension but said he was unfamiliar with this type of build.it seems nobody is interested in this type of build and i am finding impossible to get advice from anybody trustworthy

sas

wornout wrote:

hi sas
unfortunately my trust in the builder was misplaced and i had to ban him from the site,an architect had a look and said i must have ventilation in the extension but said he was unfamiliar with this type of build.it seems nobody is interested in this type of build and i am finding impossible to get advice from anybody trustworthy

From what i've come across ventilation is very necessary. Either holes in the wall, trickle vents in windows or more ideally a mechanical ventilation system.

www.fbt.ie may be able to advise as they are the main suppliers of poroton in Ireland.

smashey

This sounds like a job for vikinghouse. At the very least, there should be trickle vents in the windows. Also, is there a bathroom or kitchen in the extension?

wornout

yes there is a bathroom and a kitchen in the extension.the kitchen has a cooker hood running outside and the bathroom has a flexible hose running outside,is that enough to vent the whole extension? would be interested to hear viking house opinion as he built it !

muffler

wornout wrote:

would be interested to hear viking house opinion as he built it !

This will be interesting

wornout

hi sas
i spoke to wolfgang in fbt,he had some interesting things to say about our mutual friend(will send you a pm) however he checked the invoice for my blocks and found they where INTERNAL BLOCKS and are much denser and do not breath as well.i am waiting to hear back from him to see how i might resolve this problem. this is going to get very interesting,wait till you see my hard evidence

muffler

A word of caution here folks. Just bear in mind that the forum is for general comments and opinions. A topic can be debated in detail when its about a particular product/planning system/building method etc etc.

What wont be allowed is discussion on a users personal experiences if it entails a response from another user aligned to the alleged problem.

If I am correct here I think the OP, wornout, has had work carried out by vikinghouse. If there are problems with the building then it needs sorting out far and away from boards.ie

Im going to watch this thread very carefully

smashey

I'm all over it as well.

muffler

smashey wrote:

I'm all over it as well.

Aye - without any great effort either

wornout

a friend suggested drillig holes in the fascia and soffit and putting in plastic vents might do the trick,anyone think this might work?

Mellor

THe soffit should be vented already??? this provides air to roof space.
and drilling holes won't vent the room unless the pass directly into the room

as for the room, there should be an air supply no matter what the structure is.
check the windoes, it is possible that tricklt vents are part of the frame to get the required air changes/hour.
if there is no ventilation in the room(s) i look into getting a passive stack or similr installed. these are far better than regular holes in the wall

muffler

Mellor wrote:

THe soffit should be vented already??? this provides air to roof space.
and drilling holes won't vent the room unless the pass directly into the room

as for the room, there should be an air supply no matter what the structure is.
check the windoes, it is possible that tricklt vents are part of the frame to get the required air changes/hour.
if there is no ventilation in the room(s) i look into getting a passive stack or similr installed. these are far better than regular holes in the wall

Yes I agree with the above comments by Mellor.

Im wondering where the problem with ventilation originated? Were plans prepared for the extension and did these show the level of ventilation required to comply with bldg. regs? Was the works supervised?

wornout

there are no vents in the soffits anywhere! should there be in this type of build? i have just checked the windows and there are no vents in them.i am getting worried now.does this mean i will have to put vents at ground level through the blocks?

muffler

wornout wrote:

there are no vents in the soffits anywhere! should there be in this type of build? i have just checked the windows and there are no vents in them.i am getting worried now.does this mean i will have to put vents at ground level through the blocks?

You will definitely have to ventilate the structure but there are several issues as to how and where and possibly why. My advice would be to consult with your architect/engineer. If you had nobody retained previously you will need someone now to carry out a thorough survey of the property and prepare a report which by the looks of things you will need for future reference.

wornout

i am beginning to realise that but no architect wants to get involved,my own fault for not employing one in the first place!you live and learn

Mellor

it is possible that the soffit is vented through a small gep between boards, gat a ladder and have a close look. there can be a gap between the soffit and fascia or soffit and wall. about 5-10mm. As for the room, knocking blocks out is troublesome, look into passive stack ventilation, it is probably a good option in this situation.

kadman

Contact the block supplier and ask if you can core drill with a 150mm drill and retrofit the circular vents. Nice and tidy, and no major demo work.

kadman

Do-more

Energy depot do a heat recovery ventilation system that would probably be ideal to ventilate your extension. The ducting system they use is a preinsulated 2" duct so is 4" diameter in total, so is much easier to retro-fit.

Assuming you have attic space, you'll be able to locate the HRV unit there, fresh air intake and exhaust air outlets can be made in the soffit, so no need for drilling through the wall. The upstairs rooms can be easily ventilated through the ceiling from the attic. Downstairs may take a little bit of lateral thinking running ducts through the hot air press or wardrobes etc...

What type of heating are you using? If the extension is becoming "unbearably hot" even after the heating is switched off then logic says that too much heat has been added to the space and you need to review your heating controls.

Hope that helps, look on the bright side most people are complaining about draughty, hard to heat extensions!

ardara1

Are you complaining that the house it too well insulated?

You can't over insulate a building - if it's too hot - you're creating too much heat. If you have to get rid of it you're wasting energy.

You can have roof without ventilation - using a breather membrane such as tyvek - but it deals with moisture only - you sound as if you are looking for cross ventilation to create a cooling draft?

Its not a poroton block problem.

ardara1

wornout wrote:

hi sas
i spoke to wolfgang in fbt,he had some interesting things to say about our mutual friend(will send you a pm) however he checked the invoice for my blocks and found they where INTERNAL BLOCKS and are much denser and do not breath as well.i am waiting to hear back from him to see how i might resolve this problem. this is going to get very interesting,wait till you see my hard evidence

It doesn't matter.


How much glazing have you got to the south of the ectension - does it over heat when it's sunny? - or generally?

Ventilation is to bring fresh (hopefully warm) air in - not take warm air out.

wornout

to answer a few questions
1 i have a gas condensing boiler and i have turned down the temperature but with the weekend that was in it i rarely had the heating on
2 to the rear of the house i have a sunrooom with 2 large windows,double doors and four velux windows.house still stuffy though even with no heat on

muffler

ardara1 wrote:

Are you complaining that the house it too well insulated?


Its not a poroton block problem.

The OP merely outlined the materials used in his new extension and enquired if ventilation was necessary or if it could be done now as there was none.

He wasnt complaining about too much insulation but he was concerned that there was a lack of ventilation. He hasn't said anything about the poroton block system.

Mellor

It may feel like the buildign is overheating. But its probably a humidity problem. An unventilated room that gets alot of use will become clammy, stale and stuffy. This will be very uncomfortable and could be confused with being too warm. But the temp wont be that high, just the RH which causes the bad feeling.

I had a look through a list of ventilation services I have and a name that popped up was "". They supply all sorts of ventilation solutions, mechanical ventilation, trickle vents and passive stack venilation.
In your situation a passive stack vent would work fine, take up little space and be a good environmental solution. It would actually be better than the traditional way of doing it.

wornout

hi mellor
that passive stack has been mentioned to me before. i will google it and see what i can come up with.
thanks

anon1

You may need to look at using a pergola or other strategies to prevent excessive solar gain in the summer.

Mellor

its a ventilation problem, not a overheating problem.
Overheating should never be a problem in houses, and all will be suitable for rapid natural ventilation.

wornout

sounds like i'm going to have a great summer,if its anything like last summer.although i have polish windows that open in and you can just tilt the top part open,which should help.it would have been a whole lot easier if my builder had put vents in in the first place but there you have it,i will solve it eventually.have,nt heard of this pergola system,how does it work?

Viking House

I just spoke to Ken (wornout) and we agreed to sort out our issues between ourselves. As you can imagine there are two sides to every story.
Wolfgang's nose was in a twist because we imported blocks ourselves for a few houses.

Mellor

wornout wrote:

have,nt heard of this pergola system,how does it work?

A pergola is a garden structure that provides shade, and also a base for plants to grow up and around.