Altering Original Sashes

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sschoberg
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Altering Original Sashes

Postby sschoberg » September 21st, 2011, 7:19 am

Are we addressing somewhere the negative affect of altering original sashes? I cant find and cant remember if there is a catagory for this.

I was asked to add horizontal muntins to double hung window sashes to make them 4 lite units instead of two. A few of the sashes had some added at one point and the architect thinks they were all that way originally. Once I got them into the shop it becamne obvious that they were added and not original. They were different width then the original sash bar and some didn't even have a profile that matched the sash bars. As I explained to the GC the building looks like it was designed with the look of vertical sash bars and 3 lite sases. I'm getting much resistance but am refusing to this point.

I have also heard of other restorers being asked to route out an original sash to place an IGU in its place. And I have worked on many sashes where the sash bars and muntins were removed all together to make it easier to glaze.

Steve S
Schoberg Restorations Inc

oculus
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Re: Altering Original Sashes

Postby oculus » September 23rd, 2011, 3:50 pm

I think there certainly should be something about altering sash from their original design. There are a couple of companies in Oregon that specialize in doing the routing for IG units. It really compromises the joinery of the sash and adds quite a bit of weight. I think it is a recipe for disaster and a maintenance nightmare for the client.
The Oregon State Hospital is a perfect example of how this approach will lead to a real mess. The contractor removed the original 6 light grid, routed for one large IG unit then applied a faux 6 light grid over that. I don't give it more than 5 years before they will have maintenance problems. Not to mention how ugly it looks.

Routing of original sash should not be recommended, in my opinion.
Amy Harrington McAuley
Oculus Fine Carpentry, Inc.
http://oculuswindow.blogspot.com/
oculuswindow@gmail.com

"Opportunity is missed by most people because it is dressed in overalls and looks like work"-T.Edison

johnleeke
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Re: Altering Original Sashes

Postby johnleeke » December 16th, 2011, 7:57 pm

Steve writes:

Are we addressing somewhere the negative affect of altering original sashes? I cant find and cant remember if there is a category for this.


The newly added Principles of Work address this nicely:

Principles of Work:
viewtopic.php?f=10&t=74

Also, here are the categories you're recalling:

Classes of Treatment:
viewtopic.php?p=357#p357

Most modern energy efficiency treatments, like adding weatherstripping, would fit into the "Upgrade" classification.

However, a treatment that routs out the stiles and rails, significantly weakening the joint, and removing and throwing away the muntins would not fit in with Principle 3:

3) Existing windows can be upgraded to improve energy efficiency. Upgrading can be done in a way that limits damage and minimizes the impact on the function and aesthetics of the window.


There is a class called "Exception", which any treatment that is not specifically mentioned in the Standards might be put into. But it seems clear to me that the intent of Principle 3 is to limit damage caused by this sort of treatment. As it now stands Principle 3 looks like it might allow this treatment as an exception because of the somewhat weak wording, "can be done." If the wording was "MUST be done" then this treatment would clearly not be allow, if working by the Standards.

Both the Classes and the Principles are still at the draft stage of development and could be changed.

In my own personal view I want the Standards to be inclusive rather than exclusive. Is there a way we could include this treatment in the Standards, say as an Exception? That would allow an architect to specify "use the Standards with Maintain, Repair and Upgrade classes of work on 95 of the 100 windows on this project, and use the Standards with Exception class of work on 5 windows. This might meet Principle 3 by limiting the serious damage of this treatment to 5 windows. And the whole project would be done within the Standards.

But, I think that the intent of Principle 3 is to allow only very minor damage, such as nail holes for weatherstripping or screw holes for storm window hangers. Do we want to say how much damage is allowed?

There is also the issue of reducing the durability of the original window. If the sash joints are weakened the sash may not last as long, or if the muntins are removed, the muntin mortises have to be filled, and that filling may fail and let water into the rail causing decay and early failure of the sash.

I think, at a minimum, I have to edit Principle 3 to include durability along with function and aesthetics as the things to minimize the impact on. I'll go right over there and add that now.

Here it is:

3) Existing windows can be upgraded to improve energy efficiency. Upgrading can be done in a way that limits damage and minimizes the impact on the durability, function and aesthetics of the window.


Now, if it can be demonstrated that the rout treatment actually does impact the durability of the sash, then this treatment would not fit the standards.

The problem with this is that the owner and the architect may really want that treatment for those 5 windows and simply toss out the Standards and not use them for the rest of the windows on that project. Of course, the architect could still say used the Standards on 95 windows and don't use them on 5 windows.

Are there any conditions where this treatment could be OK? Say if they were single-light sash, and the sash were 2 3/4" thick, and made of a strong hardwood in good condition, and the insulating glass unit was just 3/8" thick, and not any wider or higher than the original glass, and the glazing rabbet only had to be deepened by 3/16" and one of the panes in the insulating glass unit was the original pane of glass from that sash? Would there still be enough strength in the joint so the sash would last just as long?

If that is possible, then someone could come on over here and write up a standard for it, and the standard could state that the sash has to be at least 2 3/4" thick hardwood, and the IGU has to be 3/8" thin, and the original glass must be used. And this method could not be used with thinner sash, or if the sash was softwood, or if the IGU was thicker. Then there would be a standard to cover this type of repair.

If there were such a standard, then our Standards would be inclusive, and more likely to be use and adopted more widely.

I'm not saying that this method should be included, I'd leave that to the window specialist who have done it. I am saying that our Window Standards will be stronger overall if they are inclusive rather than exclusive.

What do you think?

John Leeke

sschoberg
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Re: Altering Original Sashes

Postby sschoberg » December 19th, 2011, 9:32 pm

I added to this topic earlier but for some reason it did stick around. Oh well--

I'm not totally against using inclusions and stating exceptions to generally accepted practices. But do we want to allow for this particular exception? Stating the possible exception of, IGU's in original sashes will mean it would also be acceptable exception to have wood retention strips holding IGU's in place since putty cannot be used against IGU's. This definetly is not part of most original sashes.

I think the topic of basic values of standards using inclusion versus exclusion terms needs more debate!

johnleeke
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Re: Altering Original Sashes

Postby johnleeke » December 20th, 2011, 12:49 pm

OK, back to Steve's original question:

>>Are we addressing somewhere the negative affect of altering original sashes?<<

and my reply:

>>...I think that the intent of Principle 3 is to allow only very minor damage, such as nail holes for weatherstripping or screw holes for storm window hangers. Do we want to say how much damage is allowed?<<

So, let's write a standard that addresses this question. Let's write it right here and right now. We need to know what is meant by "altering sashes," and "negative effects." By "negative effects" I think we mean damage to original woodwork, or complete loss of the woodwork.

Here are some alterations that result in damage:

A. 2 screw holes to hold a temporary diagonal brace for a weak joint during sash removal
B. scraping or sanding away some surface fibers of wood from the faces of the sash during paint removal
C. removing 1/8" x 1/4" x 4" of sound wood to create a square pocket for a dutchman along a damaged margin
D. cutting three 1/16" x 3/8" x 30" slots to hold weatherstripping
E. cutting 8 mortises in a one-lite sash to add new muntin bars to convert it to a four-light sash
F. removing and throwing away muntin bars and muntins to convert a six-lite sash to a one-lite sash
G. replace a bottom rail that is 50% completely rotted away, throw away the other 50% even though it is sound wood
H. throw away the entire six-lite sash that has 3 rotten joints but other wise is sound, and replace it with a replica made of matching details and materials, because this costs less than repairing the three joints

OK, here we have a series of alterations that cause very minor damage progressing to major damage and the ultimate damage, complete loss.

Where is the dividing line between what you want to allow and not allow in this sash-alteration standard? Look at the list above and draw the line that shows where you now do your work, and where you think the line should be for this new standard. (chick on "Post reply" and tell us where you draw the line.)

Keep in mind that we have three types of treatments, each of which probably has a different dividing line: Conservation, Traditional and Contemporary. (http://ptnresource.org/WPSC_forum/viewt ... f=10&t=162) For example, G. might be acceptable in Traditional and Contemporary work, but not acceptable in Conservation work. You tell me where you draw the line, and we'll put that in the sash alteration standard.

And, how do we express the amount of loss of wood that is acceptable?
Clearly we don't have the time or space to list out all of the possibilities, and wouldn't think of every possibility anyway. Although I guess the standard could have examples, such as the list above. How about expressing it as a percentage of the total volume of the wood that makes up the sash? Then the standard could simply state:

Conservation type work allows XX% damage.
Traditional work allows XX% damage.
Contemporary work allows XX% damage.

Maybe we don't want our Standards to "allow damage", so, we could express it positively:

Conservation type work preserves XX% with no damage.
Traditional work preserves XX% with no damage.
Contemporary work preserves XX% with no damage.

What do you say gang? Let's get crackin' and write some standards!
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

johnleeke
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Re: Altering Original Sashes

Postby johnleeke » December 20th, 2011, 8:55 pm

John writes:
>>...I am saying that our Window Standards will be stronger overall if they are inclusive rather than exclusive.<<

Steve writes:
>>I think the topic of basic values of standards using inclusion versus exclusion terms needs more debate!<<

I'm not saying that our window standards need to include everything. In fact, they do specifically exclude replacing good old windows with cheap replacement windows. But, the more they can include, the more they will get used, and the more influence they will have in the character and quality of window preservation work.

We could make up a list of all the bad things that can be done to windows that we want to exclude, but the same thing could be expressed by describing the good things that can be done to windows. I'm confident that it will be a lot more fun and far easier to describe the good things that all of us are already doing to preserve windows.

Principle 3 in it's current draft would exclude routing out so much wood that the sash joints are damaged enough to reduce the life of the sash. All of us woodworkers, sash makers, and window specialists know that weakened joints are not good, but the practical question is, how bad are they? Has anyone actually see a routed out sash that has failing joints or has fallen apart?

Are there any documented cases of this actually happening? Has anyone taken photos or saved samples of sash joints failing due to routing?

Amy writes:
>>The Oregon State Hospital is a perfect example of how this approach will lead to a real mess. The contractor removed the original 6 light grid [muntins], routed for one large IG unit then applied a faux 6 light grid over that. I don't give it more than 5 years before they will have maintenance problems. Not to mention how ugly it looks.
Routing of original sash should not be recommended, in my opinion.<<

In my own work I've always recommended against routing (as it is usually done, except in one case (that I briefly describe in a message above.)
Well, as Amy says, "in my opinion", and that's the issue. This is currently a matter of opinion. It's also my opinion that routing sash is not good. And, all of our opinions add up, which is a big part of what makes the Standards project carry a lot of weight. But, what if we could convert opinion to fact?

OK, 5 years is not so long to wait. I'm betting most of us will still be around in 5 years, I know I'm planning to be. One of the things that could be done under the auspicious of the Window Standards project is to document the treatments done at the Oregon State Hospital. (I suspect it has already been done, probably by the contractor, and perhaps by the SHPOs office, I know they were heavily involved in the project.) Then check up on those windows in 2 years and 5 years and 10 years to determine their condition, document it and determine the causes. If they are then failing due to the routing, we would have some very powerful information to write a very credible standard excluding routing.
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

sschoberg
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Re: Altering Original Sashes

Postby sschoberg » December 21st, 2011, 7:58 am

Our shop has done A,B,C and D. We have never done E and F or H. (shamefull) We have done G but unless the part is just gone we'll keep it and try to reuse, with the exception of meeting rails. The one we replace are bowed so badly, they are of no use. But I have a pile of those also. Just the other day (and I can't remember the last time we ran into this) We replaced a stile becasue of extreme bowing. We were able to reuse from a salvaged sash about the same age.

I was asked one time to reconfigure a window (make it shorter) to accomadate a kitchen remodel. I did price it but the Preservation Comission denied it. At the time I probably would have done it, if for no reason other than the challenge. Thank God for this Preservation Comission. I would not do that now.

I like the idea of different allowances of damage for the three different categories. Conservation, Traditional and Contemperary. The danger zone is in the Traditional category. This is where people are struggling to make the windows more energy efficient and more maintenance free. Ha In reality then want to alter the original window to make it like new windows. I think this is a wrong direction and if we write the standards to allow this altering then most original windows at some time will be doomed. I think we should stand fast in our not allowing IGU retrofit of original windows but should show the correct acceptable methods to make them energy efficient.
Standards should list specific and acceptable damages that can be reversed or repaired.

We view contemperary sashe repair as a "do whatever" Most won't last beyond 10-15 years even with repairs. Wood is weak and joinery is non existant and the IGU's are used to give the sash more than half of its strength. Glue it, Goop it and screw it.

Repairs done for conservation seem to be governed rather strictly already. So those involved in this area will welcome added support from strict standards.

johnleeke
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Re: Altering Original Sashes

Postby johnleeke » December 21st, 2011, 7:15 pm

Steve, Excellent! This is exactly the kind of rational thought based on real experience that we need to nail down a standard on this issue.

Anyone else?
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com


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