The best method to obtain a replica of an existing sash is, of course, to furnish the sash builder with the old sash or a similar sash for an example to take measurements, match profile, duplicate joinery, and other details pertaining to that particular sash.  However, we all know this is not always an option for various reasons.  The following list will help you communicate to the sash builder exactly what it is you need.

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A NOTE ABOUT MEASURING:  In millwork all dimensions are given width by height, that is horizontal by vertical in windows.  Use a reliable tape, ruler, or scale to measure and remember to check the end hook on your tape if using one.  A bent hook will measure long on outside measurements and finish dimensions are the responsibility of the one who does the measuring.

 

IMPORTANT:  Always include glass size in you dimensions as this is a key benchmark and with the light configuration will confirm the accuracy of the rest of your dimensions to the sash builder.

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• For starters, read through the information below to familiarize yourself with what may be required of you to order a sash. Then, contact a sash builder and inquire if he can provide a worksheet to assist you in measuring your sash and providing all the information needed.  Every sash maker should be able to guide you through the process. 

• Know what type of window sash you require; single hung, double hung, plain rail, checkrail, casement, awning, etc.

• Photos always provide overlooked information.  Take and send the sash builder photos of the inside, outside, and profile of the sash you want duplicated.  Please take photos head on at a right angle to the sash.  Photos with tape measures to show dimensions are not a good way to send dimensions.

• Determine if you need an exact replica in all details or if you can use a sash made to the same face dimensions and glass size with a generic or stock profile the sash builder may use as a shop standard.  This can save money for custom knife grinding and set-ups which can be expensive, especially for a small quantity of sash.   Ask the sash builder for a detail of this profile or an actual sample to look at.

• Provide a sketch of the needed sash with all essential dimensions measured as carefully as you are able.  Measurements should be provided in face measure over glass opening size (sizes if divided light) and include overall width and height of sash.  Measure to the nearest 1/16” or closer if able.  If sash has a sill cut (angled cut) be sure to measure the longest side of the sash (long point), usually the outside.  

• If you are not familiar with face measure, take net measurements of all parts and the daylight opening sizes of the glass but be sure to convey to the sash maker your dimensions are net and daylight instead of face measure over glass opening.

• Glass rabbet depth varies in different regions and from different manufacturers.  If this is important to maintain on your new sash you may have to opt for a custom profile.

• Remember sash joints become loose and open over time so be sure to compensate for open joints in your measurements or clamp your sample sash with a bar clamp to close the joints for measuring.  

• Measuring between the shoulders of the rails at the top or bottom of the sash is a good way to get accurate overall glass opening dimensions even if sash are divided light as subtracting glass openings and muntin face dimensions from this number should equal the shoulder to shoulder rail length.

• If muntins or bars are loose in the sash, measure glass openings by measuring the shoulder to shoulder of the muntin or bar.

• Carefully measure sash thickness on the sash and between the stops where the sash travels.  Scraping, wear, and layers of paint often distort the actual thickness of the sash.  Measure in several locations on the sash.  Do not measure the thickness of the sash on the meeting rail of a check rail sash!

• Machine made sash are typically built to one of several standardized systems and the sash builder should be able to see discrepancies, if any, from your measurements and ask for verification before beginning to build the sash.

• When measuring for a pair of sash for an opening, be sure to measure the sash opening in the frame.  Width at top, middle and bottom.  Height at the left and the right. 

• Indicate if you sash is to be trimmed to your furnished dimensions or if you want the sash oversize for fitting and trimming in the field.  Badly out-of-square openings may require oversize top and bottom rails for fitting to the frame.  It is always good to have a little extra to trim, if you have the option, other than ordering a sash that may end up being too short or narrow.

• Light configurations are best described with a sketch.  Draw each sash individually if there are multiples of differing configurations.  A twelve light window is not a twelve light sash.  It is two six light sash, a six over six window.  A six over six sash is a 12 light sash.  See how a sketch can make it simpler?

• When ordering check rail sash, be sure to measure the width and height of the parting bead as this is necessary to provide the correct check rail profile.

• Some sash shops will prime or oil sash prior to glazing, inquire if this is provided on request or not.

• Indicate if the sash is to be supplied glazed or open.  If glazed, indicate what type of glass is desired.  

• Note if a particular species of wood is needed.  Ask you sash builder what wood they use when not specified.

• Specify any extra details required:  preparation for weatherstripping, plow and bore or grooved edge for hung windows, bead and rabbet joint on meeting edge of casement sash, special check rail detailing, etc. 

 

PLEASE CHECK YOUR MATH BEFORE PLACING THE ORDER FOR YOUR SASH!

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As you can see, ordering sash or windows can seem to be a complicated process but once you are familiar with the terminology and have found a satisfactory sash maker to supply your needs you will find it is not as difficult as it appears.  Your custom sash and window maker is in business to provide what you need to keep your project as authentic as you want it to be when new replica sash or windows are needed.