Best block construction methods

where stone is added to the front it is usually done so as yet another leaf makin the outter leaf 300mm thick it should be allowed for in the footing and wallties or mesh left to protrude on outside of outter leaf of blockwork to secure the stone
 
Masonchat, so concrete 1st floor means you must go with standard concrete block?? That makes things simple!

Any views on 150mm cavity, standard block construction? What thicknness of insulation... 120mm?
 
wider cavities lead to different problems.. ie your standard window frame doesnt close the cavity.. specialist jamb blocks need to be used....
your eaves detail is awkward, ...

personally, i think you should look at exactly what BER rating you want to end up with, and an approximate figure on what you want to spend on fuel every year... and then calculate backwards to see what u value of construction you need to achieve same... this will then dictate your wall construction (being within budget, of course)....

also remember that while partial fill cavity walls meet minimum regulations in theory... in practise the situation could be a whole lot different... SEI u value calculator doesnt take thermal looping into account, nor does it take into account the 'wetness' factor (a 'wet' block doesnt have the same u value as a dry block).....
 
Thanks Systhebeat,

Seems like there are so many theories on this subject!! Anyone else think wider cavity is a good idea?
 
OP well I hear you on the complaints re TF, but the fault there isn't the TF, but the way it was put together and/or the way it was finished out. There is no reason you can't have TF and the qualities you want.

Me? I have TF and concrete floors upstairs. And declaring myself here, I work for an 'alternative build system' and we've had our houses tested by the accreditation body and found ours to be well below the requirements. Again, it's all down to how it's put together - all the care in the world isn't worth a jot, if it all goes to bits on the site..........

As for wide cavities - better check with Homebond first. A friend of mine wanted to build 6" cavities on a block build recently, and Homebond said they wouldn't cover 6" cavities......................never heard that before, either.........
 
HI Fisherman, being looking at the quinnlite blocks, (wating for a quote)
how do you find house heating with Q Lite inner leaf, ? other than price issues , why didnt you use Q lite for outer leaf , did you use conc slabs or timber joist for 1st floor ? what heating system did you go with, Sorry for the questions blitz , but coming down to final decision time

...........Thanks .............
 
Ollie

I think ICF is the way forward it gives you 6 inches of solid concrete. Which Will hold the solid concrete first floor. I think Most Architects and Engineers use the same block/Cavity details because the just dont bother changing them. ICF is super warm also. worked on a hotel built with it
 
PAYEPLEB said:
Therefore the following is THE most logical cost effective method of insualting a house:
100mm standard block(outside leaf)- 100mm cavity(no insulation) - 100mm standard block(inside leaf) - 35mm Kingspan insulated slab on inside of external walls.

Forget about insulating the cavity, by the time heat has passed through the insulated slab and gone through the 4 inch block it ain't coming back!
Click to expand...

Firstly that's nonsense.
Secondly, 35mm Kingspan does not meet current Building Regulations.
Did anyone actually certify your build?
 
PAYEPLEB said:
I've just built a house with NO cavity wall insulation.

I researched and researched and researched but came to a simple conclusion - the best way to insulate a house is to stop the heat getting out!

Therefore the following is THE most logical cost effective method of insualting a house:
100mm standard block(outside leaf)- 100mm cavity(no insulation) - 100mm standard block(inside leaf) - 35mm Kingspan insulated slab on inside of external walls.

Forget about insulating the cavity, by the time heat has passed through the insulated slab and gone through the 4 inch block it ain't coming back! Spend your money on doing this internal insulation method and installing a HRV system which will control the ventilation in the house with minimal heat loss.

What harm is using long screws instead of short ones to hang stuff off an insulated wall? As long as it hangs sure isn't that the main thing!

Some people worry that if they insulate to this level they lose the thermal mass of the block walls. Well what about all the internal block walls and hollowcore mass?

Another tip is to put the insulated slab on the ceiling of the first floor. Gives you an extra layer beneath your attic insulation where most of the heat loss occurs in houses.
Click to expand...

there are lots of things wrong with this post.
as superman has said, 35mm PU foam does not meet current minimum building regulations so your construction is actually illegal. I hope you didnt get a mortgage to build this, because if you did whoever signed it off is in trouble.

secondly, heat is lost in may ways throught a building, not just through ventilation. the HRV system is not a heating system, its simply an exchange system. The most heat is lost through the fabric of the building, which you have inadequately insulated.
 
Am I correct in thinking also that insulted slab on the inside - although it helps the house heat up quickly - prevents the use of the concrete from being used as a thermal mass. therefore once you turn off the heating, insulated slab houses tend to lose their heat more quickly?

ninsaga
 
thermal mass in the irish situation is a moot point, IMHO.

PAYEPLEB is correct in stating that all the internal walls and concrete slabs act as thermal mass (even more so than external walls, which we try to insulate anyway).

The correct heating system is to have a constant heat source and exclude as much as possible heat losses.

We are too used to living in draughty, badly insulated, badly constructed dwellings where we have to load up the heating system in the morning to get heat into the dwelling, keep it intermittent throughout the day, and let it die down at night.... this is a bad heating method.
 
sydthebeat said:
wider cavities lead to different problems.. ie your standard window frame doesnt close the cavity.. specialist jamb blocks need to be used....
your eaves detail is awkward, ...
Click to expand...

Hmmm, I am about to build a house with 150mm cavity with pumped full fill insulation. Should I tell the windows people that I need these specialist jamb blocks ? What exactly are they ?
 
Birroc said:
Hmmm, I am about to build a house with 150mm cavity with pumped full fill insulation. Should I tell the windows people that I need these specialist jamb blocks ? What exactly are they ?
Click to expand...

How is your blocklayer constructing the jambs???
If you have 150 cavities you should definitely use proprietory jamb blocks... see roadstone for example... the cavity closer block.
[broken link removed]
make sure your blocklayer doesnt just lump hammer a standard block as a closer!!!!!

The windows people wont have anything to do with the block laying, but ask they what they require. Their windows will strap either side of the frame so they will need grounding.
 
building a 100m block inner leaf, a 200ml cavity with 160ml Kingspan board (2*80ml boards lapped) - 100ml exterior leaf. Wanted thick walls as building a 'traditional old world' house - the window debate above I assume is being dealt with (better check!)
 
AFAIK Cavities over 150mm will not be approved by either Homebond, or, if i am not mistaken, the concrete block manufacturers either as a structural system.
Were you advised to build like this? and have you any hassle getting it certified? Its the first time ive heard of a 200mm cavity.
 
sydthebeat said:
How is your blocklayer constructing the jambs???
If you have 150 cavities you should definitely use proprietory jamb blocks... see roadstone for example... the cavity closer block.
[broken link removed]
make sure your blocklayer doesnt just lump hammer a standard block as a closer!!!!!
Click to expand...

Excuse my ignorance but I dont see any mention of jambs in this Roadstone link.

Does jamb also mean 'cavity closer' ?
 
sydthebeat said:
AFAIK Cavities over 150mm will not be approved by either Homebond, or, if i am not mistaken, the concrete block manufacturers either as a structural system.
Were you advised to build like this? and have you any hassle getting it certified? Its the first time ive heard of a 200mm cavity.
Click to expand...

better have it checked out - architect has designed and advised - not built yet so no certification issues ...
 
i just had a good coversation with a tech guy from roadstone. His views are that whenever a non-standard system is used, ie wider cavities, it needs to be propertly detailed and designed. In the case of a 200 cavity it really needs to be designed by a structural engineer. It needs more frequent and (probably) bespoke wall ties. He suggested a wall make up of 100 outer, 200 cavity and 215 hollowblock inner, to add stability to the system. Points of instability such as opes and returns have to be especially designed. The number and locations of wall ties in these areas really should be designed by a structural engineer.

If your architect has no problem certifying then great. Can you please keep me informed of how your build goes and if there are any unforeseen issue with such a cavity, im very interested.

Re the homebond issue. They generally have no problem once the build is signed off by an architect / engineer.... but they probably wont stand over any insurance claim caused by such a structure. Will this be an issue for you?
 
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