Key Post Poroton Blocks

Re: Key Post: Poroton Blocks

Guys,

Did some more calculations and cant see the advantage of using the poroton unless I go with the T9 block. However this will still only give me a u value of approx 0.25. If i go down the parth of cavity block with internal insulation then I can can get down theoretically to 0.2 but I still have the question of breathability. I hear the talk of breathability but how much actual research is there in this area? Also if you have a heat recovery system does this prevent the breathability problem?
I went to see a Poroton house being built with the T9 blocks. Seems to be a lot more complicated than FBT imply. However as I dont intend ever selling my house I really want to future proof it so I still want to do the right thing. I think I could drive myself insane trying to get to the bottom of these questions.
Anyway, Appreciate any more thoughts on the Poroton system?

Cliffy
 
Re: Key Post: Poroton Blocks


I posed a similar question to someone on another board who seems to be well up and he put it that you could live in a plastic house and have no moisture problems if you install a HRV system. Apparently timber floors and furniture also contribute to moisture management with a house.

Drylining alone leaves parts of your walls completely uninsulated i.e. every where there is a junction between an external wall and an internal wall and at first floot level for the entire thickness of the floor in the case of a 2 storey. You could get around the floor problem though I suppose if you choose to insulate the ceiling below the floor. By cavity block do you literally mean cavity block or a 2 leaf block wall? If its the latter you could get around the first problem by insulating the cavity as normal.

What sort of complications did you see that FBT don't talk about?#

One of the more interesting features that is not being mentioned is the airtightness of poroton walls. Standard block walls are not airtight, to achieve this you have to use some sort of membrane and taping system like this [broken link removed]

Poroton is used in certified passive houses in germany from what I've read. It does achieve the required level of airtightness. This is for the wall though i.e. specific external render, block and the internal plaster. The blocks themselves do not meet the requirement.

Granted if you are planning on have a chimney then you don't need to worry about airtightness, or HRV for that matter.
 
Re: Key Post: Poroton Blocks

Thanks SAS,

Sorry Iwasn't clear. I meant 2 leaf block wall. If a HRV system is used then to me it seems that it is better to go with the 2 leaf block wall with 60mm insulation between the block and another 30mm on the internal walls and have a HRV. This would still be chaper than the poroton blocks (my quote was for over 35K).

Must now do more research on HRV systems & installers!
 
Re: Key Post: Poroton Blocks


Mine was for over 60K. Albeit it was for the T8.
 
Re: Key Post: Poroton Blocks

Sas,
I know that Vicking house would say that with 2 leaf block system you could lose up to 35% due to cold bridging, incorrect fitting of insulation etc. What are your thought on this? Is this worst case and if so would 15% be a more realistic value. Have you made a decision yet?
 
Re: Key Post: Poroton Blocks


Just so we're clear, I'm a software engineer i.e. I have no formal training\experience on this whatsoever.

However I have read alot and visited alot of sites to see various systems.
The issue of badly fitted insulation is commonly acknowledged by architects\engineers. I've read opinions of people that swear by it but that also will tell you that getting it absolutely right is very difficult.

As for the % on cold bridging I have no idea. I've been told that a house built with cavity insulation + lined with insulation backed plasterboard will give a u-value of 1.5.

1 thing that is widely acknowledged and I mentioned it earlier is airtightness. And the more I think about it the more it makes sense. An airtight structure gives the insulation the opportunity to do its job. You could have a foot of insulation lining the walls of a room but if you leave a window open the heat goes out. Obviously this is an exageration but the basic idea is still the same.

Incidently one of our fellow AAM members has justed opted for poroton, I've swapped messages with them on systems for several weeks now. If you want to get their thoughts I'll PM you're their name. I'll not mention it here to avoid them getting plagued for info.

I have to make a decision in the next fortnight. I will post back here if I opt for poroton.
 
Re: Key Post: Poroton Blocks

Thanks again SAS,
Would appreciate that contact.
 
Re: Key Post: Poroton Blocks

sas said:
Mine was for over 60K. Albeit it was for the T8.
Click to expand...
SAS what square footage was your house….2 story or bungalow?

Does any one have an opinion on the use mineral fibre insulation externally on poroton? He spoke about using paroc mineral fibre on the outside of poroton blocks to achieve passive house standards? I ran this by an engineer and he was concerned about water vapour passing through the block and meeting the cold insulation and hitting the dew point and becoming water logged. He claimed that eventually there would be destruction of the mineral fibre insulation…….do large amounts of water vapour pass through poroton blocks?
 
Re: Key Post: Poroton Blocks


3900 sq ft. part 2 store, part 1.5 storey.

However, I have read several opinions that agree with the use of an external insulation layer on the outside of a poroton wall. The issue is that the insulation must allow more water vapour through than the poroton blocks. If you go to [broken link removed] you can see that 1 of the recommended options is such a system. Wat the actual insulation is though I have no idea.

I'd be interested in what you discover. FBT weren't terribly interested in this approach however with me. Still if a few more people are showing interest in it then they miht change their minds.
 
Re: Key Post: Poroton Blocks

sas said:
I'd be interested in what you discover. FBT weren't terribly interested in this approach however with me. Still if a few more people are showing interest in it then they miht change their minds.
Click to expand...

I phoned wolfgang of FBT a while back and he didn’t see the point in external insulation as he claimed the block was good enough on it’s own. He mentioned that if you were going to have external insulation it would have to be mineral fibre insulation. I phoned weber therm who have a IAB approved mineral fibre external insulation system. Their engineer had spoken to wolfgang about getting a pallet of poroton blocks from FBT to do up a mock wall and test the system on the poroton….however this has not happened yet and weber therm sound v. expensive (around €25K for an average 2500sqft house!!!!!)
I got on the phone recently again to wolfgang and he seemed to have a change of heart about the whole passive house thing saying that they were now looking into it. I asked him could if he get hold of a new block from wienerberger in Austria ( http://www.wienerberger.at/servlet/Satellite?pagename=Wienerberger/SR_Product/ProductStandard05&cid=1172472743556&sl=wb_at_home_de ) and he said he could….I went through the wienerberger site a while back and found a similar page to the link you included in your last post…..but it was in german and it commented how these external insulation systems need ‘an over haul’ after 15-20 years (don’t do german but google translator ain’t bad!). The weber therm system is guaranteed for 60 years but it needs to be recoated after 15-20 years. Also of interest on the Austrian wienerberger website are passive house documents with diagrams which show external insulation systems used on poroton blocks…seems like it’s routine in that neck of the woods…anyway I’m going on a bit now….hoping to go to the passive house conference in Bregenz, Austria in April to find out lots more…

BTW here’s another poroton product filled with rock wool I came across (http://baupraxis.de/magazin/news/produkte/mzh_thermoplanMZ8.html ) The guy from the company claims to be the supplier of the poroton blocks used by Lidl for building their supermarkets in Ireland aka ‘lidl blocks’ The guys name is Stefan Jungk and his website is http://www.juwoe.de . He seemed eager to get into the Irish market but was not convinced by the whole passive house idea!!
 
Re: Key Post: Poroton Blocks


All interesting stuff. However, that new block is 50cm thick which makes the external walls ridiculously thick. Even the T8 at 42cm is further than I'd like to go.

All external insulation products are very expensive from what I've seen. I spoke to www.greenspan.ie about Dryvit.Given your comments on the recoating required I'm now very inclined to question the pay back period on these.

Given your plans to travel to austria are you interested in this from a selfbuild or a business point of view.

I drove past either a lidl\aldi in carlow while it was being built last year and they were using the Weinerberger blocks. Big sign hanging on the side of the building advertising it.
 
Re: Key Post: Poroton Blocks

sas said:
I drove past either a lidl\aldi in carlow while it was being built last year and they were using the Weinerberger blocks. Big sign hanging on the side of the building advertising it.
Click to expand...

Well there you go….I got the sales man line about lidl!!! I’m not going to Bregenz from a business point of view. I’ve spoken to few so called ‘passive house experts’ here in Ireland on the subject and have yet to be impressed by any of them…some of them seem to be cowboys just in it for the money. I’m going as there is an also an exhibition at the conference, like ‘self build’, of suppliers of passive house materials. I’m hoping to get information and make contacts. I’m seriously considering trying to build a passive house but if I go down that road realistically I’ll be out on my own with very little help and no backup…so I’m doing a lot of soul searching at the moment.
A few friends of mine went to see the timber passive house provided by scandanavian homes in Galway and they were hugely impressed……sounds like my friends will deal with them. Think I’ll have to give them a visit myself…It’s all done for you no hassle no trouble no headaches…
 
Re: Key Post: Poroton Blocks


Yes, and Lars Petterson is very entertaining. Saw his presentation at selfbuild last sept.

However, the cost of their homes is astronomical. If you're going passive for the environment then price doesn't matter.

If you are going passive to save money in any timeframe, then I don't see them as an option.

Do let us know though.
 
Re: Key Post: Poroton Blocks

Hi folks,

Does anyone have any info on the cost benefit's of using poroton blocks in terms of energy savings versus a build with standard 2 leaf concrete blocks? I know that it will differe depending on types if insulation and other factors, but for anyone that has used poroton blocks, did you do a cost benefit analysis on the difference before choosing the poroton option?

thanks
 
Re: Key Post: Poroton Blocks

one major concern i have with the exterior insulation is the "give" in it if it recieves a bang or nudge.from what i,ve learned you need to apply a special breathable render what happens if it gets a knock cracks or chips leaving a passage for water,you probably wont run out to your local builders merchants and buy some breathable render (exact same colour).i,ve been told that someone very heavy lets say a window cleaner on a ladder can leave dents in the wall due to the softer insulation behind the render(not saying window cleaners are heavy ,just an example!)i also spoke to a rep from kingspan who said that while we probably will see a lot more of external insulation at the minute there still seems to be problems,he mentioned a shopping centre that the render is cracking.was going to go the poroton/paroc way myself but a few people have changed my mind since,but then again i,ll probably live to regret it.still think it sounds great but i wont chance it unless its proven in ireland
 
Re: Key Post: Poroton Blocks

hi ollie30,

have you abandoned the poroton option completely, or just the external insulation aspect? just curious whether you think that the porotn option without the external insuraltion is not worth while, as I'm currently considering the poroton blocks, but I'm not farmilar with the external insulation area and how beneficial it is when used with the poroton system?
 
Re: Key Post: Poroton Blocks


I'll second that. Just because one company claims its the "be all and end all" doesn't mean that poroton\paroc offers that much of an incremental improvement over the T8 block by itself.

Plus. I spoke to Wolfgang at FBT yesterday and he said that there is an insulated render (literally plaster) that can be applied about 60mm thick on the outside of the block to bring down the u-values toward passive spec. No idea of cost yet.

However, 0.18 (i.e. T8) is pretty much unheard of from any other build type in this country. Other systems that do claim it all suffer with the soft external wall surface issue i.e. ICF or external insulation. 0.18 is also an excellant u-value. Its not as if Ireland drops below 0 degrees for 4 months of the year, albeit you never know what global warming will do!

1 thing I think we can all agree on though is that our summers are getting warmer. Porotons ability to delay the affect of external temperatues on the internal environment of a home could become very important.

The only challenge I foresee for anyone going the poroton route is getting a blocklayer (a) willing and (b) capable of getting it right. FBT claim its childs play but I'm visiting a house tomorrow that was build by a garda that grew up on building sites. He did do a fair bit of the work himself but did say that there were tricky parts where he simply steered clear and got a blocklayer to try it for him.

This is region dependant. You may find a builder in your area that is experienced with it, seems to be the case down south.
 
Re: Key Post: Poroton Blocks

sorry for the delay in the reply,yes i have abandoned the notion altogether.i really like the idea of external insulation but dont want to risk soft /damaged walls for the rest of my days.as for the poroton the t8/t9 are very very expensive i know you get a u value of 0.18 but 100mm kingspan at approx 15.50euro sqm2 (wall ties extra)or 140mm aerobord platinum at 12euro sqm2 wall ties included gets to 0.19,i know you have an element of thermal bridge and thermal looping but get a good builder and try and reduce the faults,taking these faults into account it would still be a very warm house when used with extra roof and floor insulation for a lot less money.i priced poroton and found the t12 affordable but its u value is not good enough ,just meets current regs,and from the t12 on its just too expensive in my opinion,but please suss it out yourself i'm no expert just giving my opinions and thoughts
 
Re: Key Post: Poroton Blocks

hi all
i have a two storey extension built with poroton blocks and i had the whole house insulated externally with paroc wool.the house is very warm,i have never timed the heating to come on in the morning,house retains heat no problem,however i have two problems with this type of build i have no ventilation in my new extension so the house becomes unbearably hot and stuffy. another prboblem i have is rain water from outside coming into my sunroom under the skirting boards apparently due to this single leaf system.i am not a builder so do not fully understand what my so called sustainable builder was trying to do.all i do know is he made a mess of my house.be very careful who you choose to do this work.i am all for sustainable building but there are an awful lot of chancers out there.
 
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