Hello, I’ve been lurking for a while and now have some questions about my sagging roof/attic. My house is 95 years old and located in Spokane WA. The original roof is framed with 2×4’s on 24″ centers with a 10/12 pitch. This part of the house is 24′ wide and 30′ long. The roof has some sagging. It hasn’t changed in the last 10 years. The previous owners have built knee walls in areas that were sagging worse than others but didn’t take any sag out. None of the walls are continuous or even in the same plane. I am getting ready to take the chimney out and blow in about 12″ of celulose but would like to know how best to brace the roof and if I jack the rafters back straight will they start pulling away on either end because they have taken a set.
Also I have gable vents on either end and 4 vents cut in along the roof. Should I install soffit vents and baffles before insulating or possible a fan in one gable vent.
Thank you for your time.
Replies
The original roof is framed with 2x4's on 24" centers with a 10/12 pitch.
Just in case you're interested, this is the root of your sagging problems.
would like to know how best to brace the roof
Actually, the knee walls aren't a bad idea. Collar ties, if there aren't any, would also help.
if I jack the rafters back straight will they start pulling away on either end because they have taken a set.
It is almost a sure thing that they have taken a "set". If you try to jack the bow out of them, they might pull up off of the wall plate, or away from the ridge.
You should develop a long term plan, which includes complete roof replacement. Complete, in this case, means structure, sheathing, and roofing materials.
"The previous owners have built knee walls in areas that were sagging worse than others but didn't take any sag out. None of the walls are continuous or even in the same plane."
Can you individually brace each 2x4 rafter somewhere near midspan, and check the sag with piece of straight lumber or something to get the rafters back to being straight(er)?
Proper Ventilation: Soffit vents and baffles are a must. Look at it this way, air comes in at the low point i.e. the soffits and must be allowed to circulate upward and go out at the highest possible point of the roof i.e. roof vents or continuous ridge vents at your roof peaks. I am familiar with Spokane's climate, fairly hot in summer, and cold in the winter, and moisture buildup can be a problem. I think your code minimum attic net free ventilating area is at least 1 to 150 of the area of the space ventilated. Under some circumstances this ratio may be diminished. If you check with an architect or local building dept. you can find out what is required. Because of heat buildup in the attic in the summer, I would definitely recommend a mechanical attic fan with a thermostadt, especially if you do not have mechanical air conditioning. I added one in a house in Bellevue, WA and it made a difference even on the coast where the summers are not quite so hot... I installed the fan at one gable end vent and enlarged it to the size of the fan and used a gravity wall vent (when the fan was off the vent's baffles laid flat to the wall so as to keep the cold winter air out). If you have a ceiling grille in the hall ceiling on the top floor, the attic fan will draw warm air out of the house and keep it cooler.
Insulation: I personally dislike blown-in insulation for two reasons 1) it has a tendency to settle over time, and 2) if you ever have to access the attic for any reason, it is terrible to crawl through, especially if you are doing any additinal electrical work. Blanket insulation can be moved and replaced much more readily.
You make good points about soffit ventilation, ridge vents and minimum required ventilation, but sorry bud, I'm gonna have to disagree with you on some other points. You said:
>>Insulation: I personally dislike blown-in insulation for two reasons 1) it has a tendency to settle over time, and 2) if you ever have to access the attic for any reason, it is terrible to crawl through, especially if you are doing any additional electrical work. Blanket insulation can be moved and replaced much more readily.<<
First of all, yes, blown in insulation does settle - that's why if you want 12" of coverage, you blow in 14" - or whatever. As far as crawling through the mess - real men stand on 2 feet, and yea, it sucks to work up there but life is a b****, and then you die... And, blanket insulation inherently has air leakage spaces between that batts - even with multiple layers. Around light fixtures and such, there is nearly always going to end up being air pockets and such. And, if you have only 1 layer of batt insulation, you are going to always have thermal transfer through the ceiling joists. Batt insulation in attics is for DIYs, and even guys who sell the stuff don't recommend it over blown except in places where there is no choice, even though blown in is cheaper!
As far as attic fans - yea, well, that was what we did 25 years ago... Proper passive attic ventilation will get you the required results without the power bill. And as far as the huge hole in the ceiling - maybe for a no AC house, but it is almost always going to end up being a seeping gash during the winter... Matt
How important is correcting the sags to you? It sounds as if you're mission minded on a reno here if you are taking out a chimney and putting in 12" of insul. Thus a greater repair as mentioned by the previous poster could be an option.
You didn't say anything about the present shape of the roof shingles and sheathing. At a minimum you'd want some help to those 95 yearold 2x4 rafters set 24" on center over a 24 ft wide area if I'm reading that right.
What type and how old are the present shingles and what is under them?
Are you doing this work yourself?
Edited 2/7/2004 7:25:38 PM ET by rez
We have had several discussions about how older homes don't need to be up to current codes, however, 2x4s - 24" OC - 24' roof span!!! Your rafters are probably >15' long and are way over loaded. Multiple layers of shingles don't help either. Not uncommon for that age house, but my sister had a house built about 1915 with a similar situation - they called in an engineer and 1 week later had a condemned sticker on the door!!!
Are there walls inside the house that would qualify as load bearing (supported all the way down to the footers)? If so, plan on transferring these load points all the way up to the rafters.... If not, as someone said above, start thinking about a complete roof rebuild, or at the minimum, figuring out how to get some 2x8s up there to sister up next to the 2x4s.
Sorry to be the bearer of grim news, but ya gotta make some plans to save this sloooooooooowwwwwly sinking ship!!!!
Let's see. 90 years old. Roof framing doesn't meet (or even come close to today's standards.
Been there 90 years, though. I don't think you need to duck and run {G}
I'd get a remodeling contractor out who has a lot of experience with working on old houses like yours and pay him for his time and advice to advise you on what to do.
You need someone on site to deal with the specifics of your particular house.
In older houses like that kneewalls added to support the overspanned roof rafters often transfer roof loads to ceiling joists which weren't intended to take that sort of load, and I'll be you're seeing cracks in the ceilings below which pretty much line up with the bottom of the kneewalls.
I wouldn't try to take the sag out unless it is really pronounced, and even then it should be done slowly, very slowly!
Document what you have and document the changes so you'll have historical references for when you sell the house.
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All this talk of kneewalls and bracing has given me the same worries that Bob has just expressed. If you don't follow the load path to foundation, you are just creating a problem someplace else.
You do not say whether there is a structural ridge or whether the sag is in the whole entire roof, including ridge, or if the ridge is straight and only the undersized rafters are sagging. That helps study how to correct it.I suspect it is the entire roof.
I also don't know what kind of budget you have, or how important this is to youy and whether you will live out your life there or just own it long enough to sell it again. As someone else mentioned, the present condition of the roof shingles is important.
So I am working in the blind here, but my first thought is to replace the entire roof by setting a ridge beam and framing a new roof with 2x10 at a 12/12 pitch if that would not harm the architectural integrty. This would restructure to support loads, create enough space for proper insulation and ventilation, and let you have a new roof too. Maybe worth a trip to the bank for funding.
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Your tag line gets more impressive with each passing post!
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Thanks, I'm playing with it in MSExplorer and Word. Can't figure out hopw to eliminate all the white space from between lines though.
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Piffin, I don't think ya can..prospero is set up with the line spacing..smaller font is all ya can do..
Looky, Bee helped me get my logo up..
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>>Can't figure out how to eliminate all the white space from between lines though.<<
Try using a <shift> <carriage return> rather than just a <carriage return>. Matt
Looks like your's is the one that dsid it.
Bob, when I looked at it in code, there diodn't seem to be anything quite like what you referenced, not that I ever see much code anyways.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
You need to replace the "Hard Returns" with Line Breaks. (It is simple in Word Perfect, I don't know how easy in Word.)
Try this: in Prospero, go to edit the tag in HTML, and replace the <P>s with <BR> and delete the and </P>s
_______________________
Tool Donations Sought
I'm matching tool donors to a church mission to Haiti - we're shipping a bus converted to a medical facility in (now it looks like) April and can fill it with clothes, tools and all sorts of stuff needed in that poorest of all countries. A few hand tools or power tools can provide a livelihood for an otherwise destitute family. Please email me if you have tools to donate.
Thanks to Jeff and David and Jim and Rich and Steven and Mark and Jason and Shep and Jen and Mike and Joe and Bill and Ken for their offers!
Several donations have arrived! Thanks and God bless!
Now, how's the font size look???
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
perfect from here..good job. I know it ain't easy.
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Piffin: Here is a mini HTML code lesson for you:
This line is terminated with an enter key which starts a new paragraph.
The new paragraph also inserts an extra line feed.
This line is terminated by using a shift - return key which just gives a new lineand only one line feed.
This line is just allowed to wrap automatically. The text editor here at Porspero inserts a carriage return and a single line feed for me.
On this line I changed the font size and color.
---------------------------------------------------------------------
The following is the html source code that I got by clicking the "source" button at the bottom of my edit window: (I manually changed the colors on the HTML tags to make them easire to pick out).-------------------------------------------------------------------------------------------------
<P>This line is terminated with an enter key which starts a new paragraph.</P><P>The new paragraph also inserts an extra line feed.</P><P>This line is terminated by using a shift - return key which just gives a new line<BR>and only one line feed.</P><P>This line is just allowed to wrap automatically. The text editor here at Porspero inserts a carriage return and line feed for me.</P><P>The following is the html code that I got by clicking the "source" botton at the bottom of my edit window:</P><P><FONT color=blue size=3>On this line I changed the font size and color.</FONT></P><P> </P>
-----------------------------------------------------------------------------------------------
In the above html the <P> tag is a start paragraph symbol. The </P> is a end paragraph tag, which results in the extra blank line. The <P/> tag is created when I hit the enter key by itself.
The <BR> tag inserts a Break in the text which is a carriage return and a single line feed only.
The HTML tag <FONT color=blue size=3> was atuomatically generated when I changed the size and font of the text using the controls just above my edit window. The <FONT> tag ends the font change and the font goes back to default size.
The html tags shown above <P> </P> were automatically generated when I hit the enter key 2 times. I don't know exactly what the code is, (blank space?) but I bet I could find out in about 2 minutes by Googeling for "HTML tag ". Notice that, generally, the HTML tags are used in pairs. For example <P> and <P>.
Try starting a reply window, and then click the bottom buttons between "Source" and WYSIWYG (what you see is what you get). This stuff is not rocket science, it just looks a little foriegh when you first look at it. It can get complicated though, especially when people use automatic HTML generators like Microsoft Front Page. I think most "web programmers" use some type of tool though (not really sure). You can look at the HTML source code for any web page if you are using M/S IE (Internet Explorer) by going up th the view drop down menu at the top of your browser window and selecting source. Also, when frames are used, like your main window here at BT, only one fram of the FTML is shown. Matt
FWIW, I doubt it's a structural ridge beam on a 90 year old house - they certainly didn't have that concept back then in my area (but then again, Toddely-Do is usually well behind the times in adoptiong new techniques {G})
In my area, just about every older roof is going to have some sag to it; they just didn't frame to todays standards and many times the roof have held 3 or even 4 layers of shingles!,
My thought is that replacement of the structure is probably overkill in all but the most extreme cases.
And, FWIW, (and believe it or not) those 2x4s 24" OC over a 12' span are common in my area.
_______________________
Tool Donations Sought
I'm matching tool donors to a church mission to Haiti - we're shipping a bus converted to a medical facility in (now it looks like) April and can fill it with clothes, tools and all sorts of stuff needed in that poorest of all countries. A few hand tools or power tools can provide a livelihood for an otherwise destitute family. Please email me if you have tools to donate.
Thanks to Jeff and David and Jim and Rich and Steven and Mark and Jason and Shep and Jen and Mike and Joe and Bill and Ken for their offers!
Several donations have arrived! Thanks and God bless!
Yeah, I found one once that was 2x4 on 20"-24" centers with 12' span with one layer of cedar and SIX layers of asphalt on it. There was very little sag to the structure. Of course it was true 2x4 old growth pine. A lot stronger than the SPF we get now. The house had a 1x6 shingle mould on the gables to hide the thickness of the layers.
Hey, get my email RE:lead?..cold on yer side of town?
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Repairs, Remodeling, Restorations.
As Piffin said we are working in the blind here, but I think that I agree with Bob. This framing situation is very common and is extremely unlikely to fail outright. This is only a twelve foot span on a steep roof. As long as the rafters are well tied into the ceiling joists and the top of the walls are straight, I would just add collar ties to every pair of rafters. It will probably not be possible to straighten the rafters without an elaborate system for providing outward pressure over an extended period of time. If this is a paramount consideration, reframe the roof.
FWIW, I doubt it's a structural ridge beam on a 90 year old house - they certainly didn't have that concept back then in my area
Robert
In my house there is NO ridge beam as is with the other houses in my area such as a museum I worked on last year near here.
The roof rafters (oak) butt each other with a mortise and tenon joint and then pegged.....I also don't want to leave out the carved numerals in the beams that they used to match em' all up. I forget the name for that. The historic society told me but the term escapes me.
Dose guyz never cut any corners compared to nowadayz...You think they ever heard of Makita? LOL.I think they heard more about sharpening stones.
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You are right about what used to be and about how often it did not fail, but the amt. of sag describbed here indicates to me that this house roof is in a state of failure. It needs help.
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If you insulate the attic space you should install soffit vents and baffles. When it comes to straighting out the roof ridge, you need to pull a string line down the ridge board ,then jack the ridge back into place. Before you start jacking make sure you place your jacks over load bearing walls to transfer this load to the foundation.Once your ridge is straight , you can install 2x4 collar ties from rafter to opposing rafter to hold the roof in place , or you can put posts under the ridge just make sure the post are over load bearing partitons.
In my circa:1680 house I found it interesting what some previous owners did a hundred and fifty or more years ago.
They built another roof a few inches higer than the existing roof. I think they did this to add some doggy dormers in the front of this house but if I were you I'd consider this idea to "straighten" out your problem.
Be well
andy
My life is my practice!
http://CLIFFORDRENOVATIONS.COM
"In my circa:1680 house I found it interesting what some previous owners did a hundred and fifty or more years ago.
They built another roof a few inches higher than the existing roof. I think they did this to add some doggy dormers in the front of this house but if I were you I'd consider this idea to "straighten" out your problem."
Andy,
The first house I ever considered purchasing had the exact same thing done. Basically someone pulled off the first three course of sheathing on both sides of the roof, slapped new rafters next to the old, and built a new roof over top of the old one at a steeper pitch.
Glad I didn't buy that one.
They never even bothered to remove all the old shingles!
BTW, it was a rental prop.
Jon
jon
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"hoping to see you here this summer with your brother and wives......."
Andy,
I'm pretty sure we are goin' to be out mid April. My niece is (now two) is having a big B-day bash and my bro's wife has rented out a "petting zoo" for part of the day for her (the kids) 15 closest friends. Out here we just go down the street and take them to the closest farm. Must be a LI thing?
Jon
Hello,
I'm not bothered by the sag but thought if I'm up there I might as well take it out if possible. The roof has three layers with the 3rd layer being only a few years old and looks great. The next roof will require new sheeting etc. The house does have a load bearing wall running down the center except for about 10' at the living room. I think the ceiling joists are 2x6. I measured them last summer but can't remember for sure. I was thinking of running a 2x8 on edge down the center and a 2x4 on each side and coming off of these to the mid-span of the rafters with 2x4's. Over the span of the living room I would install a properly sized beam.
The attic space would be nice to include into the living space of the house but with 2 ceilings and the work involved for everything else I would never get the money back out, at least not in this neighborhood. Thats why I'm trying not to redo the whole thing. The reason the chimney is coming out is I have to do some work in the kitchen and its in the way. Also, it probably wouldn't pass inspection and isn't being used.
We would like to sell the house in a year or two and gain some more remodeling experience in the mean time. Right now I'm trying to put together a game plan and will work out the particulars as soon as the snow melts.
Thank you for your time and experience. Greg
Try cutting the nails between the sheathing and rafters at the worst part of the swale. Get rid of the knee walls, this will allow you to sister a 2x8 to your 2x4.
Use a 6x6x10' running perpendicular too ceiling joists to jack off of. Place a temporary 4x8 of about 2/3 the length of the rafters between two rafters. Use this as a strongback to raise the roof. This should allow you to sister 2 rafters at a time.
Don't forget to re-fasten the sheathing, I think screws would work best. You may have to reinforce you seat cut with a metal strap to prevent checking.
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