Sliding Sash Window Design (Double Hung) History
The Sliding Sash Window, or Double Hung Window as its called in America, is showing a massive upsurge in popularity.
It’s an fantastically successful design. A 100 or 200 year lifespan is proven. Compared to around 20 years for uPVC windows, the timber sliding sash window is a winner.
In these days of energy conservation the traditional Double Hung Sliding Sash is unsuitable as a replacement window. Unfortunately the tradition design is unsuitable for fitting the double glazing units that regulations stipulate.
Many companies now manufacture alternative designs, some good, some in my opinion, very bad. It’s obviously a highly profitable market, with strong demand and high margins.
A couple of years ago, I embarked on project to build my own double glazed sliding sash windows. No suitable plans where available so (as a trained designer) I set about researching the subject in great detail.
This post relates to the my Synopsis of sliding sash window history. Read the article over on my website.
An understanding of historical window designs to inform 21st century developments
I’ve analysed the construction details of the Box Sliding Sash. (Available soon.) This has allowed me to fully understand the tried and tested construction. It highlights where, in the light of modern developments, the design can be evolved. I’ll be publishing construction details and plans for an evolved, traditional sash window shortly.
The final part of project will be available as a set of plans, details and explanations for a 21st century fully evolved sliding sash windows. Combining technology with craftsmanship, these windows can be built in a shed with a minimal investment in tooling.
Any comments or thoughts or INTEREST ? Please give me you feedback below.
Historial Influences on the Design of Sliding Sash Windows
I want to build my own sash windows. Is there an ebook or plans or explaination of your work? I am interested.
Hi John,
I’m working on the plans now.
I’ll be putting something together on single glazed sashes windows first.
At the same time I’m starting to build my own double glazed version. Recording all the build techniques and putting the plans together.
I’ll let you know of any progress.
Cheers
Andy
Hi Andy
I’m an English carpenter in France.
It’s strange to see that continental influences produced the sash window.All windows I,ve seen in this country open inwards instead of outward in GB.I,ve yet to see anything ressembling a sash in rural France.In fact some French clients of mine who like English
style stuff speak of sash windows as typically English. Mind you French polish is English polish in France!!?!?Really enjoyed the videos especially the door build.Thanks very much,
Regards Nigel.
Thanks Nigel,
The “tall” window style came across the channel with the architecture. In France these windows weren’t counterbalanced so not very practical. The English developements didn’t seem make it back over the water. It would be interesting to explore what political / social / climate differences caused the explosion of popularity here but not on the continent.
The inward opening casement will be where we get, what we call “French Doors / Windows”
Cheers
Andy
I have 6 windows i need to built – no rush this year but i hope your experiences will stop me having to repeat mistakes – im most interested in the tolerances of the parts to slide etc.. correctly . All my windows are modern but i have got 1 original sash from a skip down the road for my profiles etc.. Anyway enough said – i want to be kept updated please
Col
Col, Apologies for the delay in responding.
You’ve picked up on detail of tolerances and gaps so the sashes slide well. It’s a interesting point, one that’s hard to find solid info about. However I’ve nearly got my research and analysis of traditional sashes completed, it covers the”gaps”. I’ll be posting it ASAP, good job your not in a rush!
Something you should consider: If you are replacing modern windows then the new ones “should” meet building regs in the UK. That means double glazing, saftey, ventilation that can be passed by the “man from the council”. Unfortunately the old profiles won’t work for up to date windows, they cant take double glazing in a way that will last.
I am getting closer to publishing the plans for my ” High Spec” sliding sashes, I’m building 5 at the moment to check detail changes from the prototype. All I need is more hours in the day!
Cheers Andy
Hello,
The front door video was perfect timing for me as I have to make a ‘non standard’ internal door this month.
The sash window article is of interest. I have a an old house which appears to be made up of different sizes sash windows, must have been made up with leftovers from other Victorian house builds. I have made a couple of sashes using the originals as patterns but now would like to make the box section too. I have a few pages from an old book giving details of making a box sash which is enlightening but a modern version would be a better way forward so will be looking for your write up on it.
I am curious as to whether you will be using lead weights and dividers or use the the modern spiral spring mechanism. Have to admit I am not a fan of them as they look wrong.
Keep the good work up.
Regards
Terry
Terry, Glad to hear the videos are useful.
I’m of the same opinion as you when it comes to the counter balance. I don’t think spiral balances look right. I also have my doubts as to how long they will last. With the traditional weights it’s only ever going to be the cords that need replacing.
Having said that, sprial balances do make for a simplified and cheaper build and can be used when the brickwork hasn’t got the space to take the box part of the frame.
I really do need to get a move on with the window plans, I’ll see if I can accelerate progress
All the best, Andy
Posted from a recent email-
Hello
just found your site. Very interesting.
I’m as hopeless at DIY as anyone you can imagine so have decided to get a local joinery company to install wooden sash windows to help restore my Victorian workers cottage.
Am trying to make sure I ask as many relevant questions as possible . One of them has been to ask what type of softwood would be used for the box frames, sashes and cills.
The reply I’ve received re box frames and sashes is “…6th grade joinery softwood which would be treated with rot proofing liquid after assembly then primed”
On the cills, reply is “… softwood….. but utile hardwood could be used instead at slightly increased cost”.
I wondered from your experience if I should be asking further questions?
Was hoping to get this work done before Autumn but it hasn’t been possible. Someone has suggested postponing until Spring as too late in year to be doing a decent paint job on windows. Any thoughts?
There’s a few point from the above email:
Good to hear you are doing a “proper” restoration job. Just thought I should mention, if youare replacing complete windows you might have to consider building regs, unless the joinery company is acredited and sorting that side of things. It could be, that to comply the windows will have to be double glazed.
“6th grade joinery softwood” you might whant to have read of this: http://www.idostuff.co.uk/sections/DIY/Timber%20selection%202.html
SO, I’m not sure they put much thought in to that answer.
“treated with rot proofing liquid” – Some might reccomend pressure treating, no treatment is 100%. The first line of defence is to make sure the wood doesn’t get wet and stay wet. Paint (including primer) sould be good quality micropous. That combined good design should allow the timber to dry out if there is any ingress. The glazing seal or putty has to be in good condition. If the moisture content of the timber is below around 20% rot can not set in.
I’ve been using linseed oil based paints. The joinery company may not want to do this but its something to consider. have a look at: http://www.holkhamlinseedpaints.co.uk/
I know some folks will always use oak for the cills, it’s an extra precaution. However i’m happy using a good piece of softwood. After all oak will rot if its moist.
I should point out, I’m am bit pedantic. If the joinery company is good, with satisfied clients they probably know what they are doing. So may be the biggest question is, “Can I see some of the windows you have made and installed for others ?”
Hope this helps
Andy
Andy
thanks. I live in a Conservation Area and have obtained planning permission, so that aspect of work covered.
The joinery company has done my next door neighbours cottage and appear to have done a good job.
In your advice on the best timber for windows you recommend “best unsorted (U/S) redwood”.
excuse the ignorance but what does “unsorted” and “U/S” mean?
cheers
Tim
Tim,
Good to see you’ve got the planing bit covered and they did a good job next door.
U/S is Unsorted. It’s supposed to be the good bits of timber left when the poorer quality 5ths, 6ths and possible 4ths have been taken out. Although it depend on the timber merchant to carry out the grading. I choose my pieces down in the yard so at that point it is sorted, my me, for the 1sts and 2nds. For windows it needs to be fairly clear of knots with close straight grain.
Redwood is what they call the various types of Pine (not always red in colour). The quality varies bettween spiecies and the region it’s from. Whitewood is Spruce – like you get in packs from DIY sheds.
Cheers
Andy