Timber Sash Windows
Traditional looks, modern performance – without the plastic
Sash windows make or break the look of a period property. Get them wrong and the whole elevation looks off – get them right and the building looks like it was meant to.
JM Joinery manufacture bespoke timber sash windows from our workshop in Callow, Herefordshire. We design them to suit the property first, then make sure they perform properly with modern glazing, seals and hardware.
Why choose JM Joinery sash windows?
Made to measure – sized to your openings, not forced in from a standard chart.
Traditional appearance – correct proportions, meeting rails, horns and mouldings.
Modern performance – decent U-values, proper seals, smooth operation.
Options for listed and conservation work (subject to approvals).
Supply only or supply & fit within our installation area.
Types of timber sash windows
We manufacture several main sash types, depending on the property, regulations and budget.
Traditional Box Sash (Weights & Cords)
Sashes run on traditional cords over pulleys with lead or steel weights.
Ideal for period properties, especially Georgian/Victorian facades.
Smooth operation and familiar feel when built and balanced properly.
Boxes built to suit existing openings or new work.
Spring-Balanced Sash
Uses concealed spiral/spring balances instead of weights and boxes.
Useful where there isn’t room for a full box or you want a slimmer frame.
Often more practical for new builds and extensions mimicking a sash look.
Easier to work into modern cavity wall details.
Heritage / Slimline Options
For jobs where appearance is critical and planners are watching closely.
Slimmer glazing units and finer sections to resemble original single glazing.
Can be designed to meet conservation requirements (final approval is always down to the local authority).
If you’re unsure which system is right, send photos and basic info – we’ll tell you what makes sense for your building.
Timber options
We only use decent timber – what you choose depends on exposure, finish and budget.
Accoya
Very stable and durable.
Excellent for painted sash windows, especially on exposed elevations.
Good long-term choice if you’re fed up with swelling and sticking.
Hardwoods (e.g. sapele, oak, etc.)
Suitable for stained finishes or where you want visible grain.
Good durability when detailed and finished correctly.
Quality Softwood
Cost-effective, normally used for painted windows.
Works well when properly treated, finished and maintained.
Our timber comes from suppliers who support sustainable forest management, with traceability available where required.
Glazing & performance
Sash windows don’t have to be cold and draughty just because they’re traditional.
High-performance double glazing available on most sash designs.
Slimline double glazing options for more sensitive facades.
Single glazing available where conservation officers insist – we’ll be upfront about the performance trade-off.
Low-E glass, warm-edge spacers and gas fills available for better U-values.
Toughened or laminated glass where required by regs or security.
We can provide U-value figures for the specification you’re ordering if you need them for Building Control or your architect.
Detailing & appearance
This is where sash windows stand or fall:
Correct meeting rail proportions and sash horns where appropriate.
Glazing bars to match the period – through bars, applied bars or a mix depending on spec and budget.
Staff and parting beads detailed properly, not chunky plastic-looking trims.
External profiles and mouldings to suit the house, not whatever’s easiest to machine.
If you’ve got original windows on part of the building, we’ll usually work from those as the reference.
Draught-proofing & operation
There’s no point spending money on new sash windows if they rattle in the first storm.
Integrated draught seals in parting/staff beads and meeting rails.
Sashes balanced correctly so they stay where you put them.
Restrictors available for child safety and security.
Easy-clean/tilt-in options possible on some spring-balanced systems (project dependent).
We aim for windows that move smoothly, seal properly and stay put.
Hardware & security
You see the hardware every day, so we don’t treat it as an afterthought.
Sash lifts and fasteners in various finishes – brass, chrome, satin, black, etc.
Security upgrades available – additional locks, restrictors and laminated glass where sensible.
Traditional style is kept, but with modern reliability and security built in.
If security is a particular concern, let us know and we’ll design the package accordingly.
Ventilation & trickle vents
Building regulations like ventilation, conservation officers don’t like seeing vents – both can’t always be happy.
Trickle vents available where Building Control insists.
Discreet options and locations discussed at design stage.
We’ll be upfront about the balance between aesthetics and compliance and help you get something everyone can live with.
Finishes
We can supply sash windows:
Fully factory painted – best for most jobs, especially Accoya and softwood.
Stained / clear coated – mainly on hardwoods.
Primed only – if your decorator is doing the finishing on site.
Factory finishing gives better coverage and longer life, especially on exposed elevations and darker colours.
Supply Only or Supply & Fit
Supply Only
For builders/joiners who know how to fit sash windows, or where you’re outside our fitting radius.
Windows supplied glazed, finished and with hardware as agreed, ready to fit.
Collection from our workshop in Callow, HR2 8BP (delivery can be discussed depending on size and location).
Supply & Fit
Installation service within roughly an hour’s drive of our workshop.
Old windows carefully removed (as agreed), new units installed, packed and fixed correctly.
Sealing, beads and trims finished to the scope agreed in the quote – no surprises.
We’ll clearly state what is and isn’t included in the fitting price.
What we need to quote
To price timber sash windows properly, we’ll need:
Approximate sizes of each window (width x height).
How many sashes open vs fixed on each unit.
Photos of the existing windows and the elevation.
Any planning/conservation restrictions you’re aware of.
Timber preference (Accoya / hardwood / softwood) and finish (painted / stained).
Whether you want supply only or supply & fit, plus your postcode.
Drawings from your architect (if you have them) also help keep everyone on the same page.
Planning new timber sash windows?
If you’re replacing old box sashes, plastic “lookalikes” or specifying joinery for an extension or renovation:
Use the Get in touch form.
Attach photos and any drawings.
Tell us what you’re aiming for – looks, performance and budget level.
We’ll come back with straight options, clear pricing and realistic lead times – no nonsense, no sales patter, just proper information so you can decide.