pulley vs spring sash windows

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Hi,
I'm plannning to have wooden sash windows installed in my house (an old council house in need of refurbishment) but I can't make up my mind on whether I should go for the pulley system or for the spring system.

Given its particular shape, one front window will need to have 4 panels on top and 4 panels at the bottom. Basically, this window will be made out of 2 sash windows: one sash window having 2 panels on top and 2 panels at the bottom and the other sash having the other 2 panels on top and 2 panels at the bottom.

If I go for the pulley system the problem is that I'm going to have a 20 cm piece of wood right in the middle of the window (i.e. where the pulleys are going to be stored), whereas if I go for the spring system those 20 cm will be reduced down to 8 cm or so.

Now, I've heard that spring sash windows are easier to maintain but a bit harder to slide.

Does anybody know if there's any other downside to having wooden sash windows with a spring system other than the above?

I was also told that I could still go for the pulley system - if I wanted - by having a dummy sash on the 2 top left panels and a dummy sash on the 2 bottom right panels. This way the space needed for the pulleys will be reduced, however I would be able to open the window only partially.

Hope this explanation of mine isn't too messy. All I want to know is whether pulley sash windows should be preferable to spring sash windows and why.

Many thanks in advance,
Organic
 
Where I work we use Spiral Balances (Springs) all the time. There should not be a problem pushing the sash up or down as each spiral balance is ordered individually for each window.

Where a problem could arise is if the sash is wider than the height (ie. 3' wide and only 1'6" High - a 3' by 3' window would give you this), the sash might not move as smoothly as it should.

Ideally the rule of thumb for the size of an Up & Down Window is - the height should be at least double the width!

As you said your window's are replacement, therefore you have to go with the size that you have.

We very very rarely have any trouble with Spiral Balances in Up & Down Sliding Sash Windows - in fact (touch wood) - we have never had to replace one and I am working here 11 years now.
 
thanks for your answer NHG.

My windows don't have the standard sash shape so it's likely that the sash is wider than the height (unfortunately I don't have the exact measurements here with me...).

When you say that there could be a problem, do you mean a bad enough problem or something I can live with?

Thanks again for your help.
 
A problem that you won't even notice after a while. Just the movement of the sash might'nt be as smooth as if the proportions were right. Its just that the sash might "jump" a little as opposed to "glide" when opening and closing the window.
 
I'd say that you shouldn't get too hung up on pulley vs spring too much, except in the case of an historic property or protected structure. Pulley stiles do add significantly to the bulk of a window and unless your opes are large this may make your windows look chunky. Aesthetic considerations are probably more important in this than the choice of pulley vs. spring.
 
Just a word of caution about sash windows- check yours comply with fire regulations- in otherwords you have to have to be able to exit the room, and if the windows have parts that cannot be removed, they may not comply. If you have an engineer overseeing the project, you might just check with them first- or even the window company might provide you with the relevant certificate. I won't pretend I know any thing about fire regulations, but it is an important safety issue. I have MArvin wooden sash windows in my house and had to prove to my engineer that they complied with fire regs- with Marvin both top and bottom panels come out completely ( also handy for cleaning) which gives you the requisite opening. Perhaps with an older house you don't have to comply? Anyway just for your information you might check it.
 
Very good point there, you will require a clear opening 850x 500mm wide, the bottom of the window will need to be between 800 and 1100mm above the floor level.
 
New Fire Regulations 2006 are 450mm x 450mm clear ope for casement window. These came into regulation since July 2006.

The OLD Fire Regulations for Up & Down Sliding Sash were

"vertically sliding sash window should be provided with an unobstructed opening which achieves a minimum area of not less than 0.35m2. In addition the opening shall achieve a minimum dimension of not less than 500mm in either the vertical or horizontal direction"

cannot find new ones so I presume that they have stayed the same or are now smaller and the same as the casement windows.

Floor Level Regulations have remained the same as previously.
 
NHG said:
The OLD Fire Regulations for Up & Down Sliding Sash were

"vertically sliding sash window should be provided with an unobstructed opening which achieves a minimum area of not less than 0.35m2. In addition the opening shall achieve a minimum dimension of not less than 500mm in either the vertical or horizontal direction"
Click to expand...

Where did you find this- I can't find any reference to sash windows in my 1997 edition of Part B?
 
I found it on http://www.environ.ie (www.environ.ie) last year (or year before) and printed it off. It's not on our HomeBond House Buliding Manual 2000 edition or our 2006 edition either. I have tried to re-look it up on the web but as they have updated thenew fire regs sizes the vertical sliding sash one is not on it now.
 
thank you so much everybody for your kind help.

I think I'll go for the spring system then (it's also cheaper!).

As far as I understood it the panels come out entirely in the spring sash, but I'll make sure the fire regulations are confirmed by the window company.
 
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