Batten inside of Cavity Walls?

Octopus

Hi.

I've started my self build and have decided to go with the bead type insulation pumped into my cavity wall.
I'm also considering battening the inside of the cavity walls and including some extra insulation between the wall and the plasterboard.

Is this complete overkill, is the bead type insulation enough?
Also what are peoples opinion on battening the inside of external walls. Is it better to chase the walls then have the plasterer skim them?

CJhaughey

The more insulation the better, you won't regret fitting more insulation.
I am unsure as to what you mean by chasing vs skimming on the inside?
Is it that the surface is so rough that cannot fit a batten level to the wall?
or do you want to recess the battens into the wall?
Surely you could just go round with a light kango and chip off any protruding mortar if that is the problem?

Octopus

Sorry, didn't make myself clear on chasing.
I meant is it better to chase the walls for first fix wiring and plaster or is it better to batten (or blob) and plasterboard.

I have heard some people comment negatively on battening when it comes to fixing rads and bathroom ceramics to the walls.
I intend to use a 2x1 batten (1 inch thick) and then anything being fixed to that wall can be fixed through the board and into the block (if a batten is not in the right place).
This can also lead to problems if a screw is driven through between two battens, excessive tightening can dent or crack the board. A solution is to provide additional support under the plasterboard i.e. fixing a board where you will be hanging rads, sinks etc but you'd need to be very well planned in advance.

Just wondering what peoples opinions are around the whole idea of battening block walls?

sas

Octopus wrote:

Hi.
Is this complete overkill, is the bead type insulation enough?

Whic bead type insulation are you talking about? What U-value do you expect to achieve with it?

I spoke to ecobead myself this morning so I'm curious as to what you are using?

I personally like the solidity of a concrete wall so I'd avoid dry lining myself.

sas

Octopus

sas

I'm still investiagting the bead type and am about 80% certain i'll be using it.
Reports on this site are positive enough along with some other sites.
I've looked at both ecobead and warmfill but i'd like to hear more about them first.
A friend I work with has used the bead (I need to ask him what company?) and he's more than happy with it.

My thinking behind the bead is that the 'fill' is better. Using board type leaves room for too much error, loose boards, gaps, mortar in the joints, mortar across wall ties, mortar build up at the bottom of the cavity.

If your going with the bead type is the plastic wall tie type better?
I've been quoted the following from Brooks.

Standard wire wall tie - €10.40 per pack 30
Plastic Wall tie - €10.80 per pack 30

How does this look, i though you would be able to buy in bulk or a least by the 100 but this was the only stock they had.

Builderwoman!

Octpus we used warmfill...just moved in end of July and arelad really happy with performance. We also fitted Actis Tri iso super 9 (foil insultation system) to all sloped and short walls, fibre glass in attic 12 inches, rockwool in studs and put 50ml insulated plaster board fixed with mushroom scews fitted to all exterior walls. Very happy with it. Cost a good deal for all of this but already worthwhile.

sas

The ecobead platinum product gives a u-value of 0.2 in a 150mm cavity and 0.15 in a 200mm cavity according to the supplier.

These are pretty good values. Not sure of the implications of the wider cavity though. Even the availability of the longer walls ties could be a problem.

No idea about benefits of plastic over metal ties.

The system does have an IAB cert which is good.

This article from the current issue of construct ireland has an article on a house using ecobead in the walls and warmcell in the roof.

http://www.constructireland.ie/articles/0215hiddendepths.php

ardara1

sas wrote:

The ecobead platinum product gives a u-value of 0.2 in a 150mm cavity and 0.15 in a 200mm cavity according to the supplier.

These are pretty good values. Not sure of the implications of the wider cavity though. Even the availability of the longer walls ties could be a problem.

150mm will achieve 0.20 - if you discregard the increased number/size of wall ties - if you have to change from wire to strap ties you actually achieve 0.24 w/m2K - you'll also need to change heads & cill, increase your found width to 1.4m

Part L also deems that you must provide structural calcs for cavities over 150mm according to IS325

ardara1

Builderwoman! wrote:

Octpus we used warmfill...just moved in end of July and arelad really happy with performance. We also fitted Actis Tri iso super 9 (foil insultation system) to all sloped and short walls, fibre glass in attic 12 inches, rockwool in studs and put 50ml insulated plaster board fixed with mushroom scews fitted to all exterior walls. Very happy with it. Cost a good deal for all of this but already worthwhile.

Builderwoman - go back to the crowd that sold you the multi foil and get them to verify their performance - UK building control no longer accept their over-confident claims but will accept their actual measured performance of 0.60 W/m2K in a roof (Minium U-value for Ireland 0.25) it doesn't meet the regs.

sas

ardara1 wrote:

sas wrote:

.
150mm will achieve 0.20 - if you discregard the increased number/size of wall ties - if you have to change from wire to strap ties you actually achieve 0.24 w/m2K - you'll also need to change heads & cill, increase your found width to 1.4m

Can't agree or disagree with this. I spoke to them on the phone and thats what they told me. I would have hoped it was based on reality but as I said, I don't know.

How exactly do you propose that you achieve a u-value for a cavity wall of 0.2 or better.

De_man

regarding the multifoil i'm afraid ardara1 is correct, only will accept their actual measured performance of 0.60 W/m2K in a roof

ardara1

sas wrote:

ardara1 wrote:

Can't agree or disagree with this. I spoke to them on the phone and thats what they told me. I would have hoped it was based on reality but as I said, I don't know.

How exactly do you propose that you achieve a u-value for a cavity wall of 0.2 or better.

HI SAS -

All insulation will work and provide any U-value target - depending on the thickness and build-up - I don't want to recommend any particular construction - Timber frame, cavity or solid wall - just question those that are giving the solutions and do your home work. I think - if I was lucky enough to be able to build my own place would line the walls. I know the arguments about heavy/lightweight thermal mass and heavy being more suitable to take advantage of solar gain - but you're only lining the our wall - you're still left with internal walls & floors to act as 'batteries'

Octopus

Thanks for all the info everyone.

My cavity will be 105mm (dependant on brickie) which with the bead type will just give me the basic regulation U value of 0.27

Considering that, i'll most likely go with a further insulation barrier on the internal wall. Possibly insulated plasterboard but i'm favouring battening and rolling in some form of reduced width/compressed insulation.

If the insulation is foil backed does it need a vapour barrier?

ardara1

Octopus wrote:

Thanks for all the info everyone.

My cavity will be 105mm (dependant on brickie) which with the bead type will just give me the basic regulation U value of 0.27

Considering that, i'll most likely go with a further insulation barrier on the internal wall. Possibly insulated plasterboard but i'm favouring battening and rolling in some form of reduced width/compressed insulation.

If the insulation is foil backed does it need a vapour barrier?

Hi Octopus -

I think that you'll need at least 110mm grey bead to achieve the 0.27 (105 = 0.28) Compressing the insulation on the inside is no good - you must calculate the performance at the finished thickness. This also means you're putting it between battens - thermal bridging again reducing performance. Put a solid inulation on then plastic sheeting (or taping the foil) then plasterboard. Foil backed plasterboard is a vapour CHECK not barrier at every cut thru the plasterboards cut through the foil.

Viking House

Hi Octupus

I disagree with your use of polypearl and drylining internally but first I will say that I think polypearl is a lot better than partial fill cavity walling with kingspan in the cavity but you still have the problem of the 4 inch cold bridge gap all around your house where the wall meets the slab.
Insulating the inside of the wall is the wrong place to put insulation, put it on the outside where the effect is more than double. You can also insulate outside your foundations at the same time signifigantly reducing the wall/floor cold bridge.

For a better effect you should be considering denser insulation materials, polysterene has very low density so doesn't hold onto heat very long, you will need to keep putting on your heating all the time to top up the heat.
Polysterene and Polyeurethene are old technology in Scandinavia and are now used only in the foundations because you get no wind chill there.
In Finland when it is minus 30 degrees they put on the heating for 1 hour in the morning and work in that room all day because they use denser insulation materials.
The average heating cost for a 2500ft2 house in Finland is €800/year.

Mellor

ardara1 wrote:

sas wrote:

I know the arguments about heavy/lightweight thermal mass and heavy being more suitable to take advantage of solar gain - but you're only lining the our wall - you're still left with internal walls & floors to act as 'batteries'

The heavyweight thermal mass agrument is propaganda from the concrete industry. The little ads that appear in the papers on a sunday listing advantages of concrete, thermal mass is always one of them.
For thermal mass to be used correctly, it needs to be exposed. One thing that they forget to mention.
Also its interesting to put the supposed advantages of each industry in perspective. Next time you seen an ad for Quinn blocks (or similar), cut it out. Then wait for an ad from century homes (or similar). Compare the advantages they list. Puts all their propaganda out in front of you.

ardara1

Mellor wrote:

ardara1 wrote:

The heavyweight thermal mass agrument is propaganda from the concrete industry. The little ads that appear in the papers on a sunday listing advantages of concrete, thermal mass is always one of them.
For thermal mass to be used correctly, it needs to be exposed.

Don't read them.

Yea - so expose it! -

Mellor

ardara1 wrote:

Don't read them.

Yea - so expose it! -

How many people building their own home would go for am exposed concrete wall. I think people would nearly always opt for plaster finish rather than have the benefits of exposed concrete.