Injecting wall with insulation

[johnjoeville]

Hi I am due to start a self build after xmas, I am considering ICF but everyone is giving me pros and cons for all types of systems. At this stage my head is melted. Anyway at the weekend it was suggested that I build using normal cavity wall without the insulation and inject the walls full with insulation after. Anyone any comments on this system. Thanks

 

[sas]

Hi I am due to start a self build after xmas, I am considering ICF but everyone is giving me pros and cons for all types of systems. At this stage my head is melted. Anyway at the weekend it was suggested that I build using normal cavity wall without the insulation and inject the walls full with insulation after. Anyone any comments on this system. Thanks

The current edition of "Construct Ireland" magazine has a great article on a development in kildare where they built with an 8 inch cavity fully filled with ecobead platinum. Got a u-value around 0.18 if I recall correctly. If you want to go with a regular block build type and an IAB certified insulation then I think its a great solution. The Gilmarting Group in galway do it. They are very good to speak to. They also do the warmcell 300 insulation product used in roof insulation which is where I came across them.

Note that a wider cavity does introduce some additional issues e.g. wider strip foundation, need to use specialist cavity closers (I think these should be compulsory anyway FWIW) etc. You don't need to go to 8 inches though, you may be happy with the performance from a 6 inch cavity.

 

[BarneyMc]

Hi, yes I've considered this method as I believe it achieves a more snug insulation compared to rigid sheets that just will not fit tight to the cavity wall.

The big worry I have however is the chance of dampness coming from the outside across the beads and through to the inner leaf. Is this a valid concern? Thanks.

 

[johnnyg]

I plan to build in the same manner, when i was talking to the guy about the pumped bead insulation, he was telling me that its coated with a repellant. so any moisture that does get in, will flow downwards down to the damp course

 

[BillK]

We've had pumped bead insulation in our cavity walls for more than 20 years without a problem. Walls consist of two skins of brickwork with a 2" cavity.

(Mind you, the English Midlands tend to get a bit less rain than Ireland.)

 

[irishlinks]

Filling cavitys with insulation is not allowed in Scotland - because of the weather conditions. There is more chance of water moving across the cavity if there is no gap. The weather here can be wet and windy - similar to Scotland - so I wouldn't be rushing to do it if I were you.

 

[Superman]

Filling cavitys with insulation is not allowed in Scotland - because of the weather conditions. There is more chance of water moving across the cavity if there is no gap. The weather here can be wet and windy - similar to Scotland - so I wouldn't be rushing to do it if I were you.

I'm pretty sure it is allowed there - though in areas where there is much wind blown rain, 150mm cavities are required.

 

[BarneyMc]

Yes indeed it is essential that the beads repell the moisture - just hope it's true!! Indeed I got this done for my parent's house (old house with no previous cavity insulation) just a year ago and no problems.

Anyone else get this done in the last few years or more importantly has anyone come across problems with dampness using this method? If not it certainly seems attractive.

By the way it should cost less for the builder to build - no cavity insulation to fit. Get a quote for the build then inform them there will be no cavity insulation to bother about so they should drop their price!!