Cavity Wall Insulation

ciekly

Hi, We are thinking about cavity wall insulation. Could somebody recommend a company in Westmeath? And from your experience what cost is it? 4 bed house. Thanks!

DaveSave

Well C
You should expect to pay 800 - 1100 if it already has insulation in the cavity. Depends on size and access contact me and I'll google map your house for a better figure.
There's a fEw different products rock wools energy saver absorbs moisture and is hard to apply then there s glued beads , one bead is warmer than all the rest the super silver insulation beads. Then there are the spray foams which I'd say are the best as they breath the least. Timber frame needs to breath cavity wall does not.
I have all the trucks and rigs I would use the spray foams different ball game check out the Hot box test on you tube.

Dave

shane0007

DaveSave wrote: »

Then there are the spray foams which I'd say are the best as they breath the least. Timber frame needs to breath cavity wall does not.

Where did you get that information from? Cavity block walls do need to breathe as all porous materials do. What do you think the cavity is for, 1 as an insulator (air is in fact an insulator) and 2 to allow air flow behind the external wall of the cavity to dry it as this is a "wet wall".
Also open cell & closed cell spray foam insulation have varying uses & issues.

With any insulation upgrades consideration must always be given to preventing interstitial condensation which is very often overlooked. When the problem raises its weary head, many heads are left scratching & the remedial works can be exhaustive.

corkgsxr

Gap is there for a reason.

Try the outside wrap. I wasnt a fan of the idea untill I was working in a house that was done. Really works

ciekly

I know that external insulation is best solution, but it cost much more.

dathi

do not use foam in a cavity wall. as none of the foams on the market in ireland are certified for use in a cavity ,they only have certs for use in roofs. platinum beads are probable the best as far as u values go .one of the things that is regularly over looked is room ventilation as when you fill the cavity you stop a lot of air leakage from the house , and if there is not adequate ventilation in the room this can lead to problems with condensation. A lot of people mistakenly think that this is moisture traveling across the cavity through the new insulation when in fact it is moisture that is trapped in the room.

paddy147

dathi wrote: »

do not use foam in a cavity wall. as none of the foams on the market in ireland are certified for use in a cavity ,they only have certs for use in roofs. platinum beads are probable the best as far as u values go .one of the things that is regularly over looked is room ventilation as when you fill the cavity you stop a lot of air leakage from the house , and if there is not adequate ventilation in the room this can lead to problems with condensation. A lot of people mistakenly think that this is moisture traveling across the cavity through the new insulation when in fact it is moisture that is trapped in the room.

Can I ask you this.....


What sort of insulation or beads would you pump into a cavity wall with either 70mm or 80mm board allready in it??


Thanks.:)

DaveSave

shane0007 wrote: »

Where did you get that information from? Cavity block walls do need to breathe as all porous materials do. What do you think the cavity is for, 1 as an insulator (air is in fact an insulator) and 2 to allow air flow behind the external wall of the cavity to dry it as this is a "wet wall".
Also open cell & closed cell spray foam insulation have varying uses & issues.

With any insulation upgrades consideration must always be given to preventing interstitial condensation which is very often overlooked. When the problem raises its weary head, many heads are left scratching & the remedial works can be exhaustive.

Cavity blocks dont have ventilated cavitys they need to permiate not ventilate the moisture can leave from the same way it gets in......when they use cavity blocks theres no guarantee that the internal pots are ventilated as there closed at the top with a closing block that the wallplate sits on. I have seen cavity blocks that are thermally lined with fixings and bonding compounds that are perfect when stripped and have been north facing ( when there is no cold bridging different story ) any sort of a cold bridge and the moisture will penetrate and blister paint and create spurs.

I ve heard that before air is an insulator,he was an ice cream man that was insulating houses in the winter...To much air and not enough material in some products mean that the cold from the attic will breath threw it to easily definetly when its in thin 4" 6" minerqal fibers that have a very low density (bugger all material lots off air)

shane0007

DaveSave wrote: »

Cavity blocks dont have ventilated cavitys they need to permiate not ventilate the moisture can leave from the same way it gets in......when they use cavity blocks theres no guarantee that the internal pots are ventilated

I ve heard that before air is an insulator,he was an ice cream man that was insulating houses in the winter...To much air and not enough material in some products mean that the cold from the attic will breath threw it to easily definetly when its in thin 4" 6" minerqal fibers that have a very low density (bugger all material lots off air)

I am not talking about cavity blocks! I am talking about cavity walls. You cannot pump cavity blocks.

If you anything about the basics of material U-values, you would not make such a stupid comment about ice cream men, or whatever your point is.

DaveSave

One bead has a better value than the platinum bead (which has a standard lamda value) not that there s much of a difference the platinum is ecobead lamda 0.033 the super silver insulation beads are 0.031 both made in the north.

When you fill a cavity its a seperate system . there should be no air leakage between windows and walls if its built properly and sealed.Ventilation is a seperate issue.You want your home to breath just enough so its performing and safe if theres a monoxide threat.

There s vents out there that only open when moisture is detected inside the home. Wall vents and trickle window vents.

DaveSave

[QUOTE=shane007 Cavity block walls What do you think the cavity is for, 1 as an insulator (air is in fact an insulator)[/QUOTE]

Cavity block walls are nine inch cavity blocks. Cavity walls are double leaf 4 inch blocks on edge.

DaveSave

shane0007 wrote: »

I am not talking about cavity blocks! I am talking about cavity walls. You cannot pump cavity blocks.

If you anything about the basics of material U-values, you would not make such a stupid comment about ice cream men, or whatever your point is.

If the cavity block has a cold bridge section which is permeable and you then pump it with a material that is also permeable whats the problem the moisture will permiate at the surface. There are guys doing it and there product is B.S certified.

I wonder what ice cream s u value is or lamda.

DaveSave

ciekly wrote: »

I know that external insulation is best solution, but it cost much more.

OOOh i dont know about that i seen a house with external insulation and a completly empty cavity 70mm so heat leaves building threw walls and dissapites in the cavity. Other homes have so much air coming down from where drylining systems meet ceiling upstairs that the airmovement is so prolific that it cools down everything and can render the external system almost useless. Internl drylining is about 70 -80 % off the cost but traps heat right in there beside us.
External if there is solid walls with a good internal dry lining system thats insulated (Rare) or sand cement walls. Its complex enough...3mm is all you need to render sections off insulations useless.