There are a lot of different techniques to weatherstrip wood windows. Like anything, some are more effective than others. In this post I’ll show you how to install spring bronze weatherstripping on your old windows.
Spring bronze is, without a doubt, my favorite type of weatherstripping for a few reasons:
- Very attractive and gains a nice patina as it ages
- Lasts well over 100 years when installed properly
- Very effective at air sealing
- Extremely adaptable to seal gaps of various sizes
Anything that lasts as long and works as well as spring bronze weatherstripping usually requires a bit more work to install than the peel and stick weatherstripping you find at the hardware store. Once it’s installed and tuned properly, you can forget about it, and in our “no maintenance” culture today that is awesome!
Tools Needed:
- Tin Snips
- 1 1/4″ Spring Bronze
- Coppered Nails (if you live in coastal areas, use solid bronze nails)
- Drill (with 5/64″ bit)
- Hammer
- Tape Measure
You can read my previous post about weatherstripping doors here: How To: Install Spring Bronze Weatherstripping
How To: Weatherstrip Wood Windows
You’ll need to have the sashes removed from the window jamb in order to install the spring bronze. We tend to install the weatherstripping as a part of a full restoration of the jambs and sashes.
If your windows are painted shut or can barely move due to paint build up, installing spring bronze won’t do much good other than to make them even more difficult to operate.
If this is the case, prior to installation, scrape the jambs clean of the decades of paint build up so you have a smooth surface to work with. If you want your jambs primed (which I recommend) or painted, you’ll need to do this prior to installation as well. Trying to paint around spring bronze is a pain in the @$#.
If you have restored, easily operable, or windows that are even just loose in their jambs, you are a good candidate for spring bronze weatherstripping.
Step #1 Cut to Length
Measure the height of the bottom sash. Using your tin snips, cut two lengths (one for each side of the jamb). Cut them 1 1/2″ longer than the height of the bottom sash with a bevel at the bottom to match the sill angle.
For the top sash, your measurements have to be a little different. Measure the height of the top sash, add 1 1/2″ then measure the distance from the top for he jamb to the bottom of the pulley (in the case of this picture 9″). Subtract the 9″ (or whatever your measurement is from the previous number and you’ll have the length of your bronze for the top sash.
ie. Top sash height = 32″ + 1 1/2″ – 9″ = 24 1/2″
I promise the math lesson is now over. Phew!
Step #2 Pre-drill & Nail
*Caution: Spring bronze is nailed over top of the weight pocket access doors. Once it is installed, it will have to be removed is you ever need to access the weight pockets to re-rope your old windows.
If your jambs are very sturdy and the wood isn’t hard as a rock, then you can just nail right through the bronze and into the wood. If this is the case, you are a very lucky person.
I have only found one house that this worked on. The rest have had jambs that are made from petrified wood that is so poorly attached that it bounces like a trampoline with every blow of my hammer. If this is the case, you’ll need to pre-drill. Here’s how:
- Set your bronze in place on the jamb with the nail side (the flat side) facing inside the house. Make sure it is right in the middle of the jamb. There should be at least 1/16″ space between the bronze and the blind stop and parting bead to allow it to flex properly.
- Drill the first hole at the top thru the bronze and into the wood about a 1/2″. Tap in a coppered nail so it dimples the surface just a bit.
- Pull the bronze nice and tight and repeat the process about halfway down the length and again at the bottom. The second hole you pre-drill will set the angle of the bronze, so make sure it is lined up straight and doesn’t wander into the parting bead or blind stop at one end.
- Go back and repeat the process so that there is a nail every 1 1/2″ to 2″ along the length of the spring bronze.
Step #3 Spring the Bronze
Once it’s all nailed in place, go back and spring the bronze if necessary to increase the amount of gap it will fill. Test fit your window first to see if you have a snug fit or if there are gaps where the bronze isn’t running against the side of the sash.
If there are gaps, you need to bend the spring bronze out in those sections so that it puts light consistent pressure on the sides of the sash. To bend the bronze, you can gently use a putty knife to bend it back.
Alternative Installation
Sometimes I have come across windows where the jambs are just too loose to nail anything. In these cases, I have resorted to a pneumatic narrow crown stapler to install the bronze. I’m not going to lie, it goes MUCH faster! But there are a few things to be careful of if you decide to go this route.
- Use only 3/4″ stainless steel staples – Anything longer than that can get in the way of the moving weights behind the jamb. These nails will be exposed to the weather so if they aren’t stainless, they will rust and loosen their hold in a short time. Also, anytime you put two different types of metal together, you run the risk of galvanic corrosion which causes the metals to rust and corrode prematurely. This shouldn’t be a problem with stainless steel because the coppered nails are steel in their core as well. But if you use something like aluminum nails you may have a problem.
- Turn the pressure down on your nailer. It is very easy to blow right through the thin bronze with an air nailer/stapler. Test a few strips to find the right air pressure and depth.
- Still put a nail at the top and bottom of the bronze. The coppered nails hold better than pneumatic staples will. The two spots that are most likely to pull away are the end of the bronze so put a nail in those spots to make sure it doesn’t pull away in the future.
There is also a strip of bronze that can be installed at the meeting rails between the two sashes, but I rarely use it since I have found that by simply adjusting the sash lock, I can achieve a good enough seal to avoid this added expense.
Once your spring bronze is installed, you won’t have the stereotypical drafty old house anymore. Enjoy the lower energy bills and warmer winters indoors!
You can find some more energy saving ideas for an old house here: 4 Cures For a Drafty Old House
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
Hey Scott,
I’m refurbishing antique windows without weights or cords, and wonder if you can recommend some kind of jamb liner that will permit them to slide up and down with enough friction that they don’t slam down, and not so much friction that they’re almost impossible to open.
My contractor is recommending a vinyl weatherstrip (something he jerry rigged), but having huge money to refurbish the old windows in my antique house, I really don’t want the sound of vinyl every time the window opens and closes. He also tried a hard rubber product but it makes the windows almost impossible to open.
Thanks for all help!
Victoria
Try Felt or Velvet?
Hi,
Thanks for the excellent advice. Just acquired a Victorian Italianate, circa 1895, which, luckily has all the original windows, all in great shape.
I want to install bronze spring weatherstrip as you recommend but haven’t been able to locate a supplier of 100′ rolls. Any chance you’d know where I could order from and ship to Canada?
Thanks again for opening my eyes about original windows. The agent thought they were a liability and needed to be changed and factored the cost of changing all forty windows when establishing the sales price. Happy to see that far from an liability, it was a blessing (not to mention, a huge saving since we will not replace the windows).
I have insulated over 20 double hung windows with spring bronze. However, two have spiral balances. Can I use spring bronze for them? One person said there were directions in your blog for insulating spiral balance double hung windows, but I could not find it.
Hey Scott,
I’m curious, whats the reason that you extend spring bronze cut 1 1/2″ longer than the height of the sash? When using the product “stop gap” you offer in your store, can it be snagged by the spring bronze that is extended past the sash?
Thanks in advance for the reply!
My understanding is that it prevents the sash from running off the spring bronze when it is either all the way up for the bottom sash, or all the way down for the top sash.
I have 7 1/2 years on mine. First window I did that… I left the brass a bit long, sticking up past the top of that lower sash. 5 windows later, I took out the window and cut them to hide. I’m 24 windows in on 40. I do have a small thing I do for the brass. The top end, which will be hidden in the track when it’s closed, I leave 1/2 (plus) too long, and crimp it down such that the stub is behind the full bronze. That leaves a softer end. I also put one last nail in within 1/4 inch of the end. Some windows I’ve used a lot. Still no issues years on
Scott, this would be a great topic to do a video on!
Would weather stripping like this help solve the issue of freezing condensation on the inside of windows? Trying to find a solution for this dealing with subzero temps in Iowa on a 1920’s bungalow.
No, sorry. The condensation is warm house air against the coldest part of the wall plane. Because the glass just happens to be below freezing temp, the condensate freezes. You have to warm that surface:
1. Indow-Windows are interior storm windows that snap into place. They separate the warm air from the cold panes, and the dead-air gap between both glass planes keeps the Indow warm enough to not condense or freeze. These are not cheap but are how you can preserve your originals in both look and feel.
2. Less expensive but same concept is the plastic film that does the same thing. It uses adhesive so in summer when you remove it, there is some cleanup required with paint thinner or goof-off. When you apply it, you heat it with a hair dryer and it stretches tight. Much cheaper, but it is a yearly event.
3. Storm windows on exterior. Also expensive, they tend to be left up year round. They obscure the beauty of the originals, need maintenance and, when left up perpetually and combined with a lack of upkeep, will encourage a thin “trench” of deterioration of the sill wherever the moisture and sun combine their powers at that bottom drip edge of the storm windows. Also, because they tend to stay up all year, no summer ventilation.
4. Lastly, of course “ is what we did in rural Montana. Apply sheet plastic to the exterior, secured with strips of wood. These also tend to stay up so summer ventilation is gone. Plus, any nails or staples left in the sill or casings draw moisture, slowly rust, then that holds more moisture, and pretty soon you have a string of rotted outs.
All of what I wrote above is what I have experienced personally. I lived in a very leaky but lovely 1911 apartment, so I used the hair dryer plastic. Then I bought a 1911 house with 75 years of deferred maintenance and aluminum storms and siding. Also, as a kid I hated helping my single mom of 5 putting up the exterior plastic. We ALWAYS did it in the dark with a flickering flashlight, in below freezing cold.
I should add that I do not have the Indow windows. Many here in Portland do, and they love them for the look, ease of summertime removal, etc. I just still have too much restoration to go before I can start looking at those. Hope this helps!
Couldn’t have said it better Meryl!
Hi praise! Thank you.