When to replace windows

Kakes88

Currently finalising the details of our home renovation and I’ve read that windows should be one of the first thing that you do if they are being replaced. My question is, should this be done before the house is stripped out (everything is going) or should it be done after? 

FreeBear

Window fitters are well used to working in homes full of furniture & "stuff" if that's what you mean. If the rooms are clear of things that can get damaged, it is a bit easier for them.

The level of mess installers make varies from one outfit to another. The first traunch of windows I had replaced, the guy was meticulous in putting up dust sheets and cleaning up afterwards. The next lot, mess everywhere, and chunks of plaster knocked off the walls. Fortunately, the rest of the plaster will be coming off the walls so that I can insulate them. The mess is a minor consideration overall.

If you are refurbishing/redecorating, yes, get the windows fitted as early as you can.

Kakes88

FreeBear said:

Window fitters are well used to working in homes full of furniture & "stuff" if that's what you mean. If the rooms are clear of things that can get damaged, it is a bit easier for them.

The level of mess installers make varies from one outfit to another. The first traunch of windows I had replaced, the guy was meticulous in putting up dust sheets and cleaning up afterwards. The next lot, mess everywhere, and chunks of plaster knocked off the walls. Fortunately, the rest of the plaster will be coming off the walls so that I can insulate them. The mess is a minor consideration overall.

If you are refurbishing/redecorating, yes, get the windows fitted as early as you can.

Yes, the whole house is being renovated. I will get my order in then. 

Thanks for the reply.  

FreeBear

Kakes88 said: Yes, the whole house is being renovated. I will get my order in then.

If you want to avoid having trickle vents in the windows, install an alternative background ventilation system before ordering the windows. This ventilation system could be a MHRV system feeding fresh air to all habitable rooms, or a simple PIV system.

I dislike the idea of fitting a double/triple glazed window, sealing off all the could draughts, only to punch a hole in the frame to let cold air (and noise) in. On top of that, as I fit internal wall insulation around the reveals, any trickle vents in top of the frames would get blocked up. Managed to get my last few windows ordered/fitted just before trickle vents became almost mandatory in June.

Which brings us round to another point - You will be insulating the walls as part of the refurbishment ?

If you take more than 25% of plaster off an external wall in a room, building regulations kick in - They require you to insulate the walls where technically possible and with a simple payback time of 15 years. With the way the price of energy is going, it makes good sense to insulate to the best possible level.

Kakes88

FreeBear said:

Kakes88 said: Yes, the whole house is being renovated. I will get my order in then.

If you want to avoid having trickle vents in the windows, install an alternative background ventilation system before ordering the windows. This ventilation system could be a MHRV system feeding fresh air to all habitable rooms, or a simple PIV system.

I dislike the idea of fitting a double/triple glazed window, sealing off all the could draughts, only to punch a hole in the frame to let cold air (and noise) in. On top of that, as I fit internal wall insulation around the reveals, any trickle vents in top of the frames would get blocked up. Managed to get my last few windows ordered/fitted just before trickle vents became almost mandatory in June.

Which brings us round to another point - You will be insulating the walls as part of the refurbishment ?

If you take more than 25% of plaster off an external wall in a room, building regulations kick in - They require you to insulate the walls where technically possible and with a simple payback time of 15 years. With the way the price of energy is going, it makes good sense to insulate to the best possible level.

We are looking at insulation. Initially we were considering EWI but we hate the idea of covering up the bricks and features of the property, so it will most likely be internal. 

gm0

For full renovation inc roof unoccupied - I would do it after you strip out. Particularly if there is a risk that the structure varies around the building.  But if the roof isn't coming off and you otherwise aren't letting the weather in.  Then getting windows done broadly maintains weather seal bar builders with doors open and unheated.  But specification design needs to be very solid to get the window order in.

Glazing seems to be an affliction to self builders and developers, new build completion.  Config complexity and iteration. 
Delays.  Then a pallet gets dropped in the supply chain and there is repair or remanufacturing (more weeks lost).

It very easily gets on the critical path and sits there in a toad like fashion.  A staple on grand designs.
There are many things that are easier or better to do building up the inside after they go in. 
Folk wisdom is correct.  Get it specified and ordered early once the other aspects of design are sufficiently known. 

Here are just some from memory of the *many* things that go into getting correct glazing brand and product select and config for an order.  Before an attempt is made to get multiple possibilities and some competition on price.

Out or in openers

Room layouts and new and existing apertures (meeting egress)

Unfinished fights about planning conditions and obscured glazing

Aperture sizes and depths (if an old building/conversion which can vary).  Easy if taking all out. Less so if occupied.  Frame mounting depth varies by window system e.g. Velfac Alu clad the metal is cantilevered forward so the timber mounts deeper (further back) than with other systems which aren't like that for the same external wall reveal depth. Your brickwork, cavities and block work (if it's that sort of structure) may suit one system far better than another.  Hopefully yours are all the same.  Mine were not

Floor levels if playing with room use and mezzanines, galleries - that impacts safety glass and egress requirements and thus the order.

Low energy generally will make solar gain, coatings and glazing choice more complex on some compass point aspects, shading etc. vs a flat negotiate for reasonable u value 3g at a sensible price and stop.

External structural and/or secondary sills if needed, falls (to avoid water pooling) if fixing a defect to existing walls or stone apertures.  Secondary sills are easier than getting a stonemason to grind flat stone sills to be less flat but you can do either one).  But you need to allow for the sills on the window height measurement for the order.

Structure and proposed installation detail - e.g. is it a compriband install. an arbosil one, or something else timber frame related. If an expansion tape then which depth (there are wide and narrow choices), cavity closers, DPMs if wet walls without DPC, what use of air seal tapes, or full high rise rubber inners, other interior insulation depths, boarding, skimming and reveal designs, shadow gaps. Implications to frame widths selected (product choice) and end state visibility in context of all those decisions

Decision on MVHR (to avoid trickles) or picking the least worst trickle supporting window product - they vary a lot.

Handling curved heads. Limits vendor and product ranges

Planning constraints to glazing bars or full astragals.  Intrinsic to some trad styled products.  An OK unobtrusive solution on some others.  And a terrible afterthought again on some others not aimed at that market which are then the wrong choice.

Multi-section windows if access is difficult and any apertures are wildly oversize and they will be carried in and hand lifted by crew. Avoiding cranes. Section weight limit. What the profiles are for multi-section.  What the solution to better sealing is - if they aren't that good.

Supply and fit.  Or supply only for DIY self build fit.

Before you go shopping for your first window retrofit you are full of joy and hope but know nothing
Once you have done your first window retrofit procurement and fit you know the basics of how to go about it.
But you never want to do it again.
And your bank account is empty.

Best of luck