Wufi analysis

YourAverageJoe

Good Morning all,

I spent hours over the weekend trying to undertake a wufi analysis of my wall construction. I am using from outside in, plaster, 100mm block, 40 mm air void, 70mm rigid insulation board (the extra-thermal type), 100 m block, 6mm plaster, 40mm rigid board bonded to 12mm plaster board, 5 mm plaster finish.

As it was the free version of the software i had to make some compromises, i.e. weather data from vancouver (which appeared reasonabely similar to ireland) and sprayed on foam insulation in place of rigid boards (although important characteristics ver similar)

I found, based on my basic application of the software, that i did not get moisture build up behind insulated plaster board, unless i reduced the insulatiopn in the cavity drastically, i.e. down to 10 or 20 mm.

My conclusion is that condensation is not a problem if you use a decent board depth in the cavity.

Any thoughts, bearing in mind i admit only having a novices understanding of the software?

I have contacted an expert but it would take a while for him to do the simulations so i am trying to do it myself in the mean time.

YourAverageJoe

Does nobody have an opinion? Has anyone got an experience of using Wufi and the results obtained to comment?

muffler

Sorry, cant help myself but give it a wee bit of time and Im sure someone will respond

sydthebeat

youraveragejoe....

"bumping" threads back to the top is bad forum etiquette.

If posters want to post they will.

To offer my own opinion.... using a different locations meteorological data will immediately nullify any results.

sinnerboy

YourAverageJoe wrote: »

Any thoughts, bearing in mind i admit only having a novices understanding of the software?

Join the club . When I checked about 6 months ago there was only one person in Ireland who had purchased the full software licence in Ireland . That person
( not me btw ) has also taken specific WUFI training in Germany . About 30 persons had downloaded the trial version .

I don't know what the current position is . Please don't ask me to name the one person here or by pm . A little deduction is all that is required .

clint_eastman

sinnerboy wrote: »

Join the club . When I checked about 6 months ago there was only one person in Ireland who had purchased the full software licence in Ireland . That person
( not me btw ) has also taken specific WUFI training in Germany . About 30 persons had downloaded the trial version .

I don't know what the current position is . Please don't ask me to name the one person here or by pm . A little deduction is all that is required .

Whats the general consensus here? I have to admit I had never heard of it until last week (i'm not a construction professional) and when I mentioned to some Engineers/Builders/Arch Tech, either had they to any great detail. Is it necessary? I understand from another thread the theory behind it but remain unconvinced, plenty of my frends have built over the last few years and went ahead with insulated plasterboard based on the advice of the professionals engaged in their builds, granted they may have had favorable results anyway if they had done a Wufi analysis. Why is it not something that it more publicised if it has such an effect? Based on another thread it its essential to have this analysis, I thought I knew the essential stuff

YourAverageJoe

Thanks for the replies.

I know the guy you mention and have talked with him but was trying it myself to start with.

I found some interesting results but dont want to put them up here in case other people take them as proven when they are not as i mentioend i am only a noivce user.

sydthebeat

clint,

the traditional method of building was 2 4" bloc leaves with a 4" cavity. After 1992 2" of polystyrene was put into the cavity...

since then there has been 2 MAJOR revisions of the "insulation regulations" 2002 and 2008.

the issue arises when the industry offers solutions to comply with these new regulations without these solutions being properly tested and investigated. its ok to say that "my product does this"... but when its incorporated into a inhomogeneous buildup with other products its impossible for a company to take responsibility for how that product will react.

now, in my opinion, WUFI analysis for a double leaf cavity wall is over kill. drylining is not good contruction practise and simply shouldnt be used for new builds. I still cannot fathom how it still exists as a method of construction for new builds in this country.

Its much much more important, in my opinion, to get single leaf timber frame systems checked. these systems have degradable material incorporated that, if subjected to long term condensation are much more susceptible to mould growth and possible structural issues. Condensation will not result in the structural collapse of a block build.

sinnerboy

sydthebeat wrote: »

Condensation will not result in the structural collapse of a block build.

It can result in unhealthy mould growth behind the dry lining though ( as I know you know syd;))

IF dry lining an insulated cavity wall my judgement is to follow the 2/3 - 1/3 rule. Keep 2/3 insulation thickness in the cavity and 1/3 in the dry lining.

Some guidance based on WUFI simulations from our major insulation providers would be most welcome . Better still if NSAI insisted on same for inclusion on their certifications .

If you are dry lining an insulated cavity on a refurb job- fair enough .

If you are doing so with a new build - why ? . You have not been listening !

clint_eastman

sinnerboy wrote: »

IF dry lining an insulated cavity wall my judgement is to follow the 2/3 - 1/3 rule. Keep 2/3 insulation thickness in the cavity and 1/3 in the dry lining.

Whats your opinion when the 150mm cavity has fully pumped insulation?

No6

While I am completely unfamilar with the wuffi softwars I did have a good UK based software U Value Calculator Builddesk which had condensation anylsis. It was all going fine untill they decide to charge for it so I am not prepared to pay as I have plenty of free uvalue calcualtors available. When condensation becomes an issue that people are prepared to pay for an anylisis of a construction then I may consider it!!!

Based on Sinnerboy's comments wuffi is German and therefore will be complete overkill in my very humble opinion and complete with cultural sterotyping!!:D

sinnerboy

clint_eastman wrote: »

Whats your opinion when the 150mm cavity has fully pumped insulation?

For practical space saving reasons I would dry line with no more than 50mm insulation in this case .

clint_eastman

sinnerboy wrote: »

For practical space saving reasons I would dry line with no more than 50mm insulation in this case .

Thanks, this is my intention. I have contacted the supplier to carry out a condensation risk analysis for what it's worth.

YourAverageJoe

I contacted the manufactures. One did the calculation no problem. The second said that the software he used never predicted it so he said no point in running it. He said I would not have a problem with 70mm cavity and 40mm internal

clint_eastman

clint_eastman wrote: »

Thanks, this is my intention. I have contacted the supplier to carry out a condensation risk analysis for what it's worth.

The insulated plasterboard supplier has completed the condensation risk analysis and is happy that condensation will not occur. I can post up the graph if anyone is interested.
I'm happy enough to proceed with the 50mm board on this basis.