Position window out so that stone is returned to window

paulff

My home is being built with 100mm inner leaf, 100mm cavity, 100mm outer leaf with expandible 100mm metal ties on the outer leaf, followed by 200mm of stone in front of outer leaf.
Above each window opening I will hang a 150 mm (high) by 200mm deep limestone header (where bottom of header will sit flush with the top of outer leaf. external stone will also be flush with the limestone header.
The effect that I would like is to have the window sitting flush with the limetone header and the external stone work. I am thinking of pulling the window out of the cavity so that the front of the PVC is flush with the front (outside) of the inner leaf blockwork, Can somebody advise if they have done this sucessfully??
FYI: this is a new build, building window opes now!!

thanks,
Paul.

Mellor

Firstly 200mm of stone is pretty big, costly for a start. But also will reduce the light let into the opes due to large reveals.

It is possibably to get the window into the position you want, but the insulation will have to be fitted correctly, and the ope carefully detailed

paulff

I agree 200mm is too deep, realistically i ment I allowed support in footings for 200mm, in reality I will prob use 150mm of stone facing the outer leaf, but do you know how best to prevent dampness from coming in as the window will be flush against the front of the outer leaf??
What exaclty do you mean by need to do the insulation correctly?? If you run the kingspan boards in the cavity say 10mm shy of the final plaster then would'nt that be ok from an insulation perspective, i was thinking of tucking 300 strip of DPC in the cavity (all around) and folding it out ...
again my biggest concern is to prevent dampness from coming in...

gman2k

100mm outer leaf with expandible 100mm metal ties on the outer leaf....

I hope you are not using an expamet type material here....
Have a look at the Homebond book, if you don't have it, buy it.

sydthebeat

the window frame should be located at the insulation level.... the furthest forward you can bring them is onto the 100mm outer leaf, any further forward and you will have cold briges.

Slig

Its something I'm seeing more and more now, If you bring the window flush with the outer leaf of blockwork, it helps with reducing the reveals but you are bypassing your DPC and creating a coldbridge around all your windows even if you leave a cavity behind the stone.
The only way to correctly do this is to return insulation backed plasterboard on the reveals on the inside of your windows but this is determinded by the depth of your frame and you must make sure that the DPCs are in the correct location.

Mellor

Slig wrote: »

Its something I'm seeing more and more now, If you bring the window flush with the outer leaf of blockwork, it helps with reducing the reveals but you are bypassing your DPC and creating a coldbridge around all your windows even if you leave a cavity behind the stone.
The only way to correctly do this is to return insulation backed plasterboard on the reveals on the inside of your windows but this is determinded by the depth of your frame and you must make sure that the DPCs are in the correct location.

I wouldn't agree with the above.
Pushing the frame forward into the cavity doesn't increase the cold bridge, it might infact reduce it.

See attached pic, its rough i know, and elements are left out for clarity, but there is a cold bridge either way. The frame is always a cold bridge, as is the sill. Keeping the cill on the outer leaf removes this cold bridge.

sydthebeat

the furthest you can bring it is flush with the inner plane of the outer leaf. anything beyond this and you may expose the cold outleaf to the interior of the building....

paulff

What techniques should I use to Prevent dampness from driving in both sides of the windows, should I tuck in 9" DPC into the cavity and wrap this around the outer leaf blockwork?
is this effective if done carefully or is there a better technique for dampproofing windows that are flush with the outer leaf?

WUFF

gman2k wrote: »

100mm outer leaf with expandible 100mm metal ties on the outer leaf....

I hope you are not using an expamet type material here....
Have a look at the Homebond book, if you don't have it, buy it.

What is wrong with using expamet? Homebond book says its not suitable, but gives no reason. Have seen it used frequently wih no apparent problems.

topcatcbr

Mellor wrote: »

I wouldn't agree with the above.
Pushing the frame forward into the cavity doesn't increase the cold bridge, it might infact reduce it.

See attached pic, its rough i know, and elements are left out for clarity, but there is a cold bridge either way. The frame is always a cold bridge, as is the sill. Keeping the cill on the outer leaf removes this cold bridge.

Interesting
What happens in plan

blackiebest

What you should do is install the window on the inside face of the outer block in line with DPC. You should then plaster the 100mm block reveal and finish your stone to the block. You will find that the stone work can never be plumb nor straight and sealing the gaps between the (plumb and straight) window and the varying stone work is almost impossible and frankly should not be attempted IMO. Traditionally all rough stone buildings were plastered/dashed and for good reason, it is only in the last twenty or so years that the 'stone house' look became popular (personally I think they are apalling and a waste of lots of money). Cut stone buildings such as banks, courthouses etc were masoned utilising skills now long forgotten leaving plumb and square chiseled blocks to which a window could be sealed.

See attached image of the only way I think it should be done.

Hope this helps.

topcatcbr

Where is attachment Blackie

blackiebest

oopps, no image last time, sorry.

blackiebest

Thats it Top,

Sorry still getting head around how to attach images. Anyone explain how to post the actual image as opposed to the link?

Thanks,

Blackie.

topcatcbr

i think blackie that this is what they are trying to avoid

i will post a detail later

blackiebest

Fair enough Top, but rough stone to a window is, in my opinion, a bad detail and should be avoided if you want a reliable seal. It never was done traditionally and for good reason. Many people, who do not know better, want to achieve a particular look or result which is not possible when other factors eg weather rain etc are considered. Banging silicone or mortar into the gaps leaves a crap seal (long term) and is really only as good as the person who applies it.

By the way MODS, is it ok that I also leave my business website address after each post like TOP? I understood this was not ok

Mellor

topcatcbr wrote: »

Interesting
What happens in plan

Pretty much the same, closed
I should point out that the window was supposed to remain over the cavity, I sort of rushed it, window over cavity with slate closer,

blackiebest wrote: »

Thats it Top,

Sorry still getting head around how to attach images. Anyone explain how to post the actual image as opposed to the link?

Thanks,

Blackie.

You have to click on this button
Ands then post the URL of the image (so it has to be online and not on your PC), a way around this is to attach it, then use the above button to link to the attached address.

blackiebest

blackiebest wrote: »

By the way MODS, is it ok that I also leave my business website address after each post like TOP? I understood this was not ok

Thanks for that Mellor will try it and see how I get along:), notice you are a Mod here, can you advise me on putting my business weblink here like Top does with impunity?

Thanks

topcatcbr

blackiebest wrote: »

Thanks for that Mellor will try it and see how I get along:), notice you are a Mod here, can you advise me on putting my business weblink here like Top does with impunity?

Thanks

Sorry I didnt realise it was a prob

topcatcbr

Detail as promised

topcatcbr

blackiebest wrote: »

Fair enough Top, but rough stone to a window is, in my opinion, a bad detail and should be avoided if you want a reliable seal. It never was done traditionally and for good reason. Many people, who do not know better, want to achieve a particular look or result which is not possible when other factors eg weather rain etc are considered. Banging silicone or mortar into the gaps leaves a crap seal (long term) and is really only as good as the person who applies it.

:

I agree it is not ideal but it gives the desired visual appearance of a solid stone wall and not a wall with stone stuck to it (which it is).

blackiebest

Honestly Top, for me its not a problem, I am happy for people to be able to show others what they do, especially when they share areas of interest. I am in the window business but as I understand it I am prohibited from mentioning my company, however this seems to be only applied if a Mod deems it to be 'pimping' for business!

On topic now. Your detail is one which would apply to square, plumb and true materials. I note with humour the neat silicone joint, works on paper, have a look at some stone houses and see the finish between ope and window. As a manufacturer and installer of top end windows we refuse to seal between rough stone and window. This is the clients problem BECAUSE there is no good way of doing it. Your detail is good except that all your lines are straight and do not reflect the materials we are discussing, rough stone is not reflected in your drawing. The best I have seen is when stone work is completed before window installation with a baton fixed to the reveal at the window position, then the stone is pointed to the baton and later the baton removed and replaced with the window. Easy and logical but try to get a builder to do it :mad::mad: Anyhow I still think all these 'stone' houses look like sh1t and are a crazy waste of money by people who really cant afford it. Would be much nicer to see them buy some nice trees for there never finished gardens.

topcatcbr

blackiebest wrote: »

On topic now. Your detail is one which would apply to square, plumb and true materials. I note with humour the neat silicone joint, works on paper, have a look at some stone houses and see the finish between ope and window. As a manufacturer and installer of top end windows we refuse to seal between rough stone and window. This is the clients problem BECAUSE there is no good way of doing it. Your detail is good except that all your lines are straight and do not reflect the materials we are discussing, rough stone is not reflected in your drawing. The best I have seen is when stone work is completed before window installation with a baton fixed to the reveal at the window position, then the stone is pointed to the baton and later the baton removed and replaced with the window. Easy and logical but try to get a builder to do it :mad::mad: Anyhow I still think all these 'stone' houses look like sh1t and are a crazy waste of money by people who really cant afford it. Would be much nicer to see them buy some nice trees for there never finished gardens.

I know what you are saying i used to make and fit aluminium windows along time ago. but as a designer I try to give the clients what they want (if its a good idea or not) I will tell them what i think if i feel they might listen. It does not look right if the lay person can tell by looking at the finished wall that the stone is stuck to a layer of blockwork. this also applies when the front facade meets the gable and there is a strip of stone on front side of building. just looks like lazy design work. IMO

muffler

blackiebest wrote: »

By the way MODS, is it ok that I also leave my business website address after each post like TOP? I understood this was not ok

A small link in your sig isnt going to ruffle any feathers here but if you post any link or details of it when replying in a thread or constantly refer to your business then the feathers will fly

blackiebest

Thanks for the clarity Muffler, you were the one I was worried about:D Will put into my sig now and tell Top the same. Please let me know if any feathers are being ruffled but genuinely I am not here to Pimp as I am sure Top isn't.

Cheers,

Blackie.

muffler

blackiebest wrote: »

Thanks for the clarity Muffler, you were the one I was worried about

Glad to hear that. The day you stop worrying about me is the day that I pack it in

Its called good moderation.







Now I must go and pat myself on the back.

Slig

topcatcbr wrote: »

I know what you are saying i used to make and fit aluminium windows along time ago. but as a designer I try to give the clients what they want (if its a good idea or not) I will tell them what i think if i feel they might listen. It does not look right if the lay person can tell by looking at the finished wall that the stone is stuck to a layer of blockwork. this also applies when the front facade meets the gable and there is a strip of stone on front side of building. just looks like lazy design work. IMO

I read a post by Sinnerboy somewhere suggesting different methods of construction. He mentioned a system where the inner leaf of blockwork is 215mm and is built with the wall ties in place up to wallplate level. this sorts out your structure. The insulation can then be applied properly with all joints taped, sorting out your insulation to a much higher standard. The outer leaf can then be built up in 100mm blockwork neatly meaning the cavity is done properly, there shouldnt be any mortar droppings and the wall is more structurally sound (even with an increased cavity). Your stone could then in theory be used to replace the outerleaf of blockwork cutting out this problem.
What amazes me is how opposed people are to doing anything different like this! Even though it makes perfect sense people keep flogging the dead horse of the traditional cavity wall.

Oh and I agree with blackie, Landscaping is never done properly. It forgives a lot of design issues. trees are brilliant shelter, look nice and arent expensive. They can even dry up your garden if you have a water problem.

topcatcbr

Slig wrote: »

I read a post by Sinnerboy somewhere suggesting different methods of construction. He mentioned a system where the inner leaf of blockwork is 215mm and is built with the wall ties in place up to wallplate level. this sorts out your structure. The insulation can then be applied properly with all joints taped, sorting out your insulation to a much higher standard. The outer leaf can then be built up in 100mm blockwork neatly meaning the cavity is done properly, there shouldnt be any mortar droppings and the wall is more structurally sound (even with an increased cavity). Your stone could then in theory be used to replace the outerleaf of blockwork cutting out this problem.
What amazes me is how opposed people are to doing anything different like this! Even though it makes perfect sense people keep flogging the dead horse of the traditional cavity wall.

Oh and I agree with blackie, Landscaping is never done properly. It forgives a lot of design issues. trees are brilliant shelter, look nice and arent expensive. They can even dry up your garden if you have a water problem.

Very good alternative
I might use this someday.
This would also be great for suspended conc first floor.

RKQ

Interesting.
Why not check out English robust details?
It is traditional in England to install timber windows flush with the outer leaf of brick!
The windows are installed and the walls built around them.
Their Building Regulations are similar to ours and they may have a product that addresses the "cold bridge" problem.
Consider a second dpc at head , reveals & cill of stone / external block junction.

Mellor

blackiebest wrote: »

Thanks for the clarity Muffler, you were the one I was worried about:D Will put into my sig now and tell Top the same. Please let me know if any feathers are being ruffled but genuinely I am not here to Pimp as I am sure Top isn't.

Cheers,

Blackie.

Sorry I didnt reply,
i was looking for a post on the poker forum that reltes to here,

http://www.boards.ie/vbulletin/showpost.php?p=52920958&postcount=1


Thats the sig link guide lines