Tuesday, October 23, 2007

The Wooden Storm Window Project

When we removed the wood sashes for rehab, we had to remove several storm windows from the house. The storm windows were in really tough shape. Even though they were only 10 years old (from dates found written on them) most of them were completely useless -- the glass panes were inoperable (stuck) and the screen material had ripped. In short, they were a complete bust.

We decided at the same time we worked on the wood windows that we would have to replace the storms at the same time. There were no storm windows on the front (south) side of the house, and these were the sashes that were in the roughest condition. Thus, not only did we end up deciding to replace the storms on the north side which we had to remove as part of the rehab, we also had to install storms facing the south (which is the side facing the street).

Similar to the wood windows, we had several concerns with replacement. First, we didn't want something that would detract from the value of the home -- and let's face it, ugly silver aluminum storms do exactly that on a 300 year old farmhouse. Second, we needed something that was going to be relatively inexpensive, because we didn't want to invest a lot in storms if ultimately we decide to replace the windows entirely at some later point.

We took external measurements for each of the windows, and did some online research. The Cambridge Historical Society recommends 'Harvey'triple-track aluminum storms (1 upper fixed glass pane, and 1 lower glass pane interchangeable with a screen) for people who need to install traditional storms. Unfortunately Harvey windows are only available from contractors, homeowners cannot buy them direct. With some research we found Boston Building Materials Corporation, a co-op in Boston, allows homeowners to buy them direct. Unfortunately, they ran just over $100 per window, which meant the total project would be over $700, and we would have those ugly aluminum storms. Definitely not an option we wanted to choose.

We did a little shopping around. A similar aluminum storm windows would run $80 each at Home Cheapo for 'Larson' windows. This would put the project at just over $550, which was a little more palatable. Unfortunately, we simply couldn't get over the 'ugly' aspect of these aluminum storms, so we decided to look for another option and instead choose this only as an absolute 'last resort'.

Visiting a few other historic homes in the area, I noticed many of them had a wooden structure with a 2nd pane of glass in front of the double-hung unit. When I did research online, I found that these 'wooden storm windows' are fairly common on older homes, but have fallen out of favor due to their higher maintenance requirements. I found a local company, Smith Restoration Sash, which manufactures custom wooden storms (keep in mind this project was ongoing at the same time as our sash rehab project). Unfortunately, Smith Restoration Sash charges $185 per window in the dimension we were looking for, so this priced this option outside our budget entirely.

Checking around some more, we saw on several windows what we ultimately determined was an aluminum 'picture storm'. A picture storm window is simply an aluminum frame with a single large pane of glass that mounts in the frame. In the summer, you change out the glass pane and install a pane containing a screen.

We really loved the idea of a picture storm. We were really hoping our rehab project would turn out well, and we wanted to implement a storm window solution that would allow us to enjoy the full look of our rehabbed windows without ugly cross-braces you find on the triple-tracks. An aluminum 'picture storm' seemed like the ideal solution!

That was, unfortunately, until we did some investigation on the price. Inquiring about Harvey picture storms, we found the price was going to be in excess of $200 per window! Larson makes a picture storm we could purchase at Home Cheapo, but even their prices were going to be in excess of $140 per storm window. Both options completely outside our price-range for the project.

I gave this a little thought, and I thought I could construct my own picture storm windows, out of wood, using existing tools that I already owned. I also estimated the cost should be about the same or less than what I would pay for the Larson Triple-Track storms from Home Cheapo -- or roughly $500.

I was correct. In total the project ran a little over $400. Lumber to construct the windows cost $125. Glass for the 8 windows I constructed cost $190. The hangers for the windows ran another $20, and I spent another $50 on felt insulation and silicon caulking compound. I also had to buy a router bit that ran $30.

Building frames is fairly simple. I opted to use a mortise and tenon setup for the frames, with an inner 1/2" rabbet. I had all the tools already to manufacture these frames -- a table saw, tenoning jig, and dedicated mortising station. The remaining of this blog entry will discuss the steps we undertook to manufacture the storms.

Step 01: Cut boards to length

Weekend One. I donned my newest plaid shirt, and went to the barn sans workshop to begin the project.

For our choice of lumber, we opted to use popular, which is an extremely stable wood with good milling properties. We purchased 8 1x6x8' pieces at a local lumberyard -- Home Cheapo doesn't carry this size of board, and we wanted a higher quality than what you normally find at the local discount shops. The total price (with tax) was just over $125, which was $1.89 a board foot.

Using the measurements we previously made, we cut each board to length, to make the rails and stiles.

Step 02: Rip boards in half

Oncethe pieces were cut to length, we ripped each board in half, resulting in the rails and stiles being exactly 2.75" wide. You may ask "why not simply buy 1x3 popular and use that instead?" Our main reason for using wide popular boards is by cutting a 1x6 to length and then ripping in half with the table saw, we had two board which were exactly the same length. Had we used 1x3 boards, there would be minute variations for each cut and each rail and stile would be slightly different in length, resulting in an out-of-square frame. Although this step required some addition work on our part, it helped insure we would have a square frame.

Step 03: Make shallow cuts

After ripping the boards in half, we adjusted the table saw to make shallow cuts 2 inches from the edge. Each cut is a quarter inch deep. This will form the end of the cheek cuts and leave a 1/4" tenon in the center of the board.

Step 04: Edge cut for blind tenon

In addition to the horizontal cheek cuts, we made an additional vertical 1/2" cut 2 inches from the edge. This is to form what is known as a blind tenon. The edge of the tenon on the rails will not show through the top or bottom of the stiles. This was accomplished by simply adjusting the blade height to 1/2" and running the board thru vertically.

Step 05: Complete Cheek cuts

Using my tenoning jig, I completed the cheek cuts on the table saw. The cheek cuts are simple with this jig, which runs slightly over $100 at Home Cheapo and works with virtually every Delta table saw. The wood is held securely against the jig, the jig adjusted to the left to ensure the cut only takes out the material it is supposed to. Two passes are necessary, one for each side, simply rotate the piece 180 degrees and pass thru again. Also, because I made blind tenons, it was necessary to adjust the jig a 3rd time and run each piece thru after rotating the wood 90 degrees, to remove the 1/2" of material for the blind tenon.

Step 06: Finished tenon

Here we have a picture of the completed tenon. Notice the tapered end. This is done automatically by the jig by holding it at a slight angle to the saw blade. This taper ensure the piece fits smoothly into the mortise.

Step 06(b): Finished tenon showing blind cut

Here is another angle of the same cut, showing the blind tenon. This cut ensures that the tenon does not appear along the top or bottom edge of the stile. This helps ensure the joint is a lot stronger and will not prone to crack and break over time.

Step 07: Setup Mortise station for mortises

After all the rails were milled with their tenons, our attention turned to making the mortises in all the stiles. To do this, we broke our our dedicated mortising station. This is a truely wonderful tool, which both drills and chisels the mortises at the same time. If you do not have one of these tools, which run about $250 via special order at Home Depot, then you can use a relatively inexpensive forstner bit and a drill press (or hand drill) with a sharp chisel to accomplish the same thing.

Step 08: Set depth to 2"

The first step in making the mortise is to mark where the mortise is going to be located. Notice the stop and start lines on the wood, and how the stop line is 1/2" from the edge of the board. This will form a mortise to house the "blind tenon" we previously made with the tenoning jig.

Step 09: Make mortices

The dedicating mortising machine makes short work of the mortises. Simply press down, let the drill and chisel do the work, and then lift the handle, adjust the wood, and repeat.

Step 10: Clean out mortices

Under the classification of "things norm never tells you", while the mortising machine is quick, it does leave quite a bit of compacted material at the bottom of the mortise. The only way to get it out is to use a small screwdriver, chisel, etc, to dig the material out.

Step 11: Finished Mortice

And there you have it, a completed mortise, ready to accept a tenon.

Step 12: Setup for Plug cutter

Before we do any setup and gluing, I needed to cut some dowels to use as plugs. I used a special polyurathane glue which foams as it cures. The side-effect of this is it will "push" the tenon out of the mortise as it foams and expands. To prevent this from happening, you are supposed to clamp the frame. Unfortunately, I don't have enough clamps to simultaneously manufacture 8 frames, so instead once the frame is built I intend to drill and plug each tenon joint with a dowel. Using a special plug-cutting bit on my drill press, and some spare popular, I made 32 dowels -- four for each frame, one for each corner.

Step 13: Finished dowels

Here are the finished plugs cut from the spare popular. Pretty, aren't they?

Step 14: Glue and Assemble frame

Frames are now ready for assembly. I used a special waterproof glue which foams when it cures. To use this glue, you moisten both pieces you intend to join together, apply some of the glue, and then attach the pieces together. The water activates the glue chemically and it starts to "foam and cure almost instantly. Unfortunately, no pictures of this step, just insert the tenons into the mortises and use a rubber mallet to tap into place.

Step 15: Check for Square

I moved the assembled frame to my workbench to complete installation. Once assembled I have about 5 minutes of 'work time' before the glue starts to foam and set up. I need to pin the joints with a dowel before this happens, but before I do this, I need to check the frame for square. A simple way to do this is to use a tape measure to measure corner-to-corner. If the diagonals are equal, the frame is square. If the frame isn't, I made a few adjustments either left or right to square it.

Step 16: Drill for dowels

With the frame square, I drilled for the dowels. Put a small piece of scrap wood underneath the joint to prevent blow-out and drill all the way thru. The idea here is once the dowel is inserted in place, the tenon will not be able to back out of the mortise as the glue foams and cures.

Step 17: Tap in dowels

Dunk the dowels in water and then spread some glue on them. Tap the dowels into place so they are flush with the surface. If you do not have a drill press or plug cutters, you can buy pre-made dowels at Home Depot in the Tools section.

Step 18: Set frame aside to dry

Put the assembled frame aside to dry. It takes 24 to 48 hours for the glue to cure, depending on humidity. In my case, I was working on the windows at the same time, so these sat in the barn over the week until the following weekend.

Step 20: Scrape off Glue

Weekend Two.

Pull the frames from the wall, and start cleaning them up for the next phase of work. When the glue foams it makes a mess as it comes out the joints. Use a paint scraper to remove all easy stuff.

Step 21: Sand joints smooth

Use a sander to sand the edges smooth. There are always minute variations when you make the mortises and tenons, so there is usually a small edge. A random-orbit sander is an excellent choice for this, but in my case I had my handy belt-sander to do it for me.

Step 22: Remove glue from inner corners

A chisel or razor knife helps clean out any foamed glue which is inside the joint on the frame.

Step 23: Prepare Chamfer bit

Now that all the glue is cleaned up, it is time to break out the router to make the rabbets and edge details. First I used a 45 degree chamfer bit to create a small chamfer on both the inside and outside front edge.

Step 24: Route front inner edge

To make the inside chamfer, I wanted to insure I had enough "meat" on the back of the frame to support the rabbet, so I adjusted the depth of the chamfer cut to slightly less than a quarter inch, and ran the router along the inside edge.

Step 25: Inner Edge Detail

A picture of the completed inner chamfer cut. This cut is necessary because you want an angle where the frame meets the glass so any water that hits the glass will run down and off the wood, and not pool on the wood, or worse, work its way behind the glass and onto the inside of the frame.

Step 26: Repeat on outer edge

Repeat the process on the outside edge. This isn't strictly necessary, but it creates a raised panel / shadowbox effect which looks neat and professional.

Step 27: Prepare rabbeting bit

Now that the chamfers are done, it is time to route the rabbets into the frame. I had to purchase a 1/2" rabbeting bit at Home Depot. I had a 1/4" bit but I wanted to create a slightly deeper rabbet. A Porter-Cable 1/2" rabbeting bit costs $30, but they are worth every penny with their carbide cutting surfaces.

Step 28: Rabbet inner back edge

Run the router along the inside of the frame. With a rabbet this deep it is best to do it as two steps -- first with the 1/4" bit and then with the 1/2" bit. This helps with removing material as the larger bit has to work less. I didn't do this this time, but it is a "lesson learned" for the next time I manufacture these frames.

Step 29: Completed Rabbet

Here's a photo of the completed rabbet. Unfortunately the router does not leave us with square corners, so we have some additional work to do.

Step 30: Chisel corners

You can use a regular chisel to square off the edges, but I have a set of edge chisels sitting around. Pulling out the 1/2" edge chisel, I'm ready to go.

Step 31: Rubber mallet to complete corners

Tap the edge chisel gently into the corner with a rubber mallet. Don't whack it too hard, otherwise, the chisel will blow thru to the other side and I'll have a completely ruined frame!

Step 32: Complete with chisel

After removing 99% of the material, I had to use a regular chisel to clean up the edges.

Step 33: Completed corner

There's a completed corner. Repeat the process for the remaining 3 corners, for 7 additional frames.

Step 34: Measure Sill Angle

The sills on This Old Farmhouse have a taper. This taper has to be transferred to the bottom of the storm window frame to help insure an accurate fit. Using a angle gauge, I obtained the angle from the window...

Step 35: Transfer to circular saw

...and transferred it to my circular saw, which I used to make the cut. Working with a frame this large means the table-saw was out as an option, it would simply be too unwieldy to make the cut accurate, without building a special jig to run the pieces thru the saw. Too much work, I had a more elegant solution with the circular saw.

Step 36: Measure out for sill cut

The blade on the circular saw is 1.5" from the edge. With the angle removing some material, I determined I needed to set a straight-edge 2" from the bottom of the frame. Clamp the straight edge to the frame at each end.

Step 37: Make sill cut with circular saw

No pictures of the actual saw process, hard to operate a circular saw and take a picture at the same time :) Suffice to saw, simply turn on the saw and use the straightedge to guide the cut. You end up with a smooth, straight cut, at the corrent angle thanks to correctly transferring the angle to the circular saw.

Step 38: Prepare for weep holes

The final step in this phase of assembly is to drill some weep holes for any moisture to work its way out from behind the window. This is a common mistake in old wooden storms, they do not have any way for the accumulated moisture to work its way out. Without weep holes, moisture collects and eventually rots the frame (or the sill). To drill the weep holes, I used a 1/4" forstner bit and my hand drill

Step 39: Drill Weep holes

Place the bit against the wood at the appropriate angle, a simple eyeball measurement suffices...

Step 40: Drilled weep hole

...and complete the drill process. I also placed a piece of scrap wood against the back of the frame to prevent blow-out as I drilled the hole.

Step 41: Clean up edges with chisel

A chisel makes quick cleanup. Then, use a piece of sandpaper and run it over all the sides of the frame to clean up any loose sawdust or fibers which need to be cleaned off. A quick coat of linseed oil to prepare the frame for painting, and put them aside for the remainder of the day.

That's it. Weekend Two is complete.

Step 42: Primed and Painted frame

Starting Week 3, we applied two coats of linseed oil, a coat of primer, and two coats of finish latex paint to match the trim, giving a day or two between coats for the paint to cure, depending on humidity. Our parlor was briefly transformed into storage as we lined the windows along the wall to dry.

Step 43: Mounting Hardware

Figuring out how to hang the storms was problematic. You would think this wouldn't be a problem, but finding screen and storm hardware for hanging windows is nearly impossible at local hardware stores. After all, nobody uses this type of hardware any longer.

At first I was going to use "turn buttons", but this would have required I mount additional strips of wood to the existing trim to hold the storms in place. This wasn't a viable option since it would require additional priming and painting outside, and the nights are getting too cold now for painting.

After some intensive research online (thanks Google!) I discovered Stanley made 'kits' which consisted of two hangers, eyehooks, and screws to mount a storm or screen window. The kits ran $2.39 each plus shipping (averaging $3 total per kit w/ shipping) from a vendor via Amazon.com.

Step 44: Install hangers

Normally you would mortise the hangers into the frame, but in this case because I'm putting on insulation anyway, it really doesn't matter if they are not mortised. Simple flush mount will work.

Step 45: Silicon Rabbets

Once the hangers are on, we were ready to install the glass. Our glass sheets were 28"x53", double-strength glass. Even with double-strength glass it took both of us to manipulate the sheets. We started by first placing a small bead of silicon along the inside of the rabbets. This provides for a waterproof seal once the glass is in place.

Step 46: Install glazing points

To provide some extra strength, we placed glazing points at regular intervals along the inside of the frame after the glass was in place. Then we ran an additional bead of silicon along the frame and glass to seal the glass in place. Unlike our wooden windows, these panes of glass have the rabbet facing inward, not outward, so we really didn't feel like using glazing compound (nor did we see the need to, the silicon is hidden 'inside'.

Step 47: Frame with glass installed

Here's a picture of a glazed frame. You can't even see the glass. Truly wonderful.

Step 48: Install insulation

To help provide an airtight seal around the window, we added some felt insulation around three edges (top and sides). The idea behind a storm window is you create an airspace between the storm window and the house window to provide a form of "airlock", which helps provide some insulating value (plus helps keep the weather off the main windows, prolonging their lives.)

Step 49: Insulate sill

We also insulated the bottom of the frame where it will sit on the sill. The felt insulation will allow any moisture behind the window to wick thru the felt.

Step 50: Notch weep holes

Naturally, we also needed to notch out the insulation from the weep-holes, to help aid any moisture in getting out from the backside of the window.

Step 51: Frame ready for installation

Finally, our storm windows were ready for installation.

Step 52: Install mount points

Weekend Four is upon us. Installation outside is really simple. Center the storm window where you want it to live on the sill, and mark where to install the hangers above the window on the trim. Then drill and install screws.

Step 53: Mount points on Trim

The mounted hangers look like this. By purchasing a few extra sets of hangers, we'll be able to make wooden screen windows in the spring and simply swap the storm windows for screen windows when the temperature gets back to a comfortable level outside.

Step 54: Tilt and install frame

To install the window, simply tilt it against the hangers and slide them into place. An audible "click" lets you know they're in place.

Step 55: Fit frame to sill

Set the bottom of the storm window on the sill. If we measured correctly (which we did!) then there is a little resistance from the felt insulation. However, a little push and the bottom slides into place nicely.

Step 56: Drill pilot holes

To keep the storm frame from flapping around in bad weather, and to help secure it against the sill trim, Stanley includes eyehooks to fasten the bottom.A pilot hole with a drill is necessary here to keep the wood from splitting.

Step 57: Attach securing latches

We screwed in the eyehooks and their cooresponding secure points on the sills.

Step 58: Secured frame

And finally, the frame is secured. The window is done!

Step 99: Finished Project!

And there you go. A completed wooden storm window. Notice we painted the bottom rail of the storm window black to match the windows. This helps "hide" the storm window. From 10 or 15 feet away, you cannot even tell they are there, they blend so well with the rest of the home!

This was a really positive project. We are absolutely thrilled with the way these windows came out. We are really happy with their appearance and utility.The sound-deadening effect is dramatic. Of course, we can't attest to their utility in keeping drafts and whatnot out of the house, we'll have to post a followup to this blog entry in the spring.

There are a few things we would have done differently (and may go back and do before winter hits anyway.)First, the felt insulation really wasn't suitable for this application. It doesn't seal very well against the trim of the house. During installation of the windows we noticed some 'gaps' between the insulation and the felt. I think we're going to have to scrap the felt insulation and install install the foam-rubber self-adhesive insulation. The foam rubber insulation is more spongy and we believe will provide a much better insulating seal.

We're also not happy with the eyehook mounts provided by Stanley. We'd like to find some other type of securing system which we can use interchangably with the screen windows when we manufacture them in the spring. Next time we're at home depot we intend to look around the hardware section and perhaps experiment with different options.

Finally, I have to give special thanks to my mentor, without his knowledge, this project would have never have been successful!

Thanks Norm!