Converting interior opening to an arch
Lyptus
| Posted in Construction Techniques on
I want to widen the opening between my living room and kitchen. It is currently a 40″ wide rectangular opening which I want to widen to about 72″ and frame it as an arch with no moulding in attempt to give the opening a southwest look and feel. Does anyone know of any magazine articles or hints on how to build an interior arch opening?
Thanks,
Lyptus
Replies
Rather than being concerned with the "look", you need to consider the structural ramifications of widening the opening first. Is it a load bearing wall? Will you need a header? Any electrical in that section of wall?
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
How do you determine if it is load bearing wall? If the opening currently has a header should I assume it is load bearing? If it has a header, are there ways of extending the header without replacing it completely with a longer one? I'm thinking of some sort of lap joint that could be used to extend the header and extra two feet?
There is an electrical outlet in the side wall that must be moved so I'm prepared for that.
- Lyptus
No, it would not be practical to try to extend a header. After you opened the wall completely, you could saw carefully and replace one side of the header at a time.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
> How do you determine if it is load bearing wall?
The answer is long enough that I wrote up a FAQ for it a while ago:
How to identify bearing walls:
When somebody asks how to identify load bearing walls, it's usuallybecause they're thinking of removing a wall or cutting a big hole inone. That can be serious business, not something that can be designedadequately by using a FAQ from the internet. The following discussionmay be useful for the preliminary speculation phase of such a project,but don't rely on it for anything more.
Removing a load bearing wall is not impossible, but it is moreexpensive. Often much more expensive. It will require some sort ofsubstitute support for the weight it carried, usually a beam. Oftenthis beam will have to be large enough that it extends downward fromthe ceiling fairly far. On a top floor, you may be able to hide it inthe attic, and hang the ceiling joists from the side of it, or evenfrom the bottom. But often the ugly beam sticking down, which alwayslooks like you took out a wall, defeats the architectural purpose ofremoving the wall in the first place.
You'll also have to provide adequate support under the ends of thebeam, because the load that was formerly distributed along the lengthof the wall is now concentrated there. This load has to be supportedall the way down to the ground.
The official code definition of a bearing wall is any wall thatsupports 100 pounds or more per foot of length, and any masonry wallthat supports any additional masonry above its ceiling level. That'snot particularly practical or helpful, since there's no instrument tomeasure the weight on the top plate of a wall.
In general, you have to look at what the wall supports, and whatsupports it. Walls that are parallel to the joists above are usuallybut not always non-bearing. On my top floor, I have a wall parallelto the joists that supports the rafter tails of a decorative roofsection. On the top floor, always look in the attic to see if thewall in question carries any roof load. Then look to see if itsupports ceiling joists. If the joist tails rest on a wall, it'salmost always bearing. I have one exception to that upstairs, wherethe ceiling joist tails rest on a non-bearing 2x3 wall that was thepartition between two closets, each 10 feet by 27 inches. On eachside, the real bearing walls are only 27 inches from this partitionwall. They form the sides of the stairwell.
Taking that idea a bit farther, you may want to analyse the wholehouse, figuring out from the top down how the weight of all thematerials and contents are supported all the way down to the ground.That's the way engineers design structures, from the top down. Theyhave to do it that way, because they can't design any part of thestructure until they know the weight of the stuff it supports.
In the past, certainly in the 1920's, building codes used to allow 2x3's for non-bearing walls. Then for quite a while 2x4's were the minimum for all walls. I know that started prior to 1971, but I'm not sure how far prior. Now with the 2005 code, 2x3's are allowed again for non-bearing walls. It's possible that you'll find a load bearing 2x3 wall if bootleg remodeling removed a nearby bearing wall.
For ground floor walls, look in the crawl space or basement. Abearing wall perpendicular to the joists should be no more than onejoist depth away from some sort of support -- a girder or cripplewall. That's a code requirement for all walls, not just on the groundfloor. So, if your joists are 2x10's (actually 9 1/4"), and a wall is10 inches away from the nearest support, it's probably not supposed tobe bearing. The exceptions are if the original design was done by anengineer, or the building is old enough to pre-date that code.
In old houses, bearing walls parallel to the joists below may have noextra support. In newer construction, they'll usually have a joist ortwo under them. The best practice is two joists with space betweenthem for utilities to run into the wall without hacking up thestructure. As always, beware of bootleg jobs that may havetransferred loads to walls that legally shouldn't carry them.
The tough part comes when you have three or more stories, and you wantto work on the in-between floors. First, you should start from theattic and work down, because any bearing wall up there has to besupported by bearing walls all the way down. Then look in the crawlor basement, and work your way up. As with the crawl space, the maxis one joist depth away from floor to floor, unless it's an engineereddesign or an old building. Next you may need to do some exploratorydemolition of the ceiling to see what's on top of the wall inquestion. Again you're looking for joist tails, this time floor joisttails.
Finally, even if a wall appears to be non-bearing, if it'sperpendicular to the joists above, you have to determine the size ofthose joists and the new distance they'll span if the wall is removed.If there are no walls or roof load supported by those joists, you canlook in the span tables to see if the result will pass code. If theysupport other parts of the structure, engineering calculations arenecessary.
Most people at this point should hire a structural engineer. If youdon't want to hire an engineer, get some engineering books from thelibrary. Unless you have a very strong technical and math background,that kind of light reading will probably convince you to pay somebodywho already knows this stuff. Even if you have the ability to learnenough for a simple job, an experienced engineer's second opinion maywell provide you with a more cost-effective solution and save you morethan the engineer's fee.
Most jurisdictions will require a licensed engineer's wet stamp on plansbefore they issue a permit for structural work. So even if you couldlearn enough to do it yourself, your local building department may notaccept it because they don't have the resources to check your work.
What you may be able to do for yourself is measure and draw. If youcan make good accurate measurements and drawings of what you have andhow you want to change it, you may find an engineer who will do yourjob from your drawings, without the expense of a site visit. Some willeven do simple jobs via fax.
A general contractor or rough carpenter might also be able to give youan expert opinion on whether a wall is bearing or not. Please don't askfor a "free estimate" if you don't intend to hire someone for the job.The fair thing to do is pay them their hourly rate. That might be abouthalf what an engineer would charge for a site visit.
Also, non-bearing is merely a legal term used in codes. It doesn'tmean that the wall in question has no structural role. Gravitydoesn't care whether we call a wall bearing or not. After it's gone,the floor above may be less solid feeling, even though it still passescode.
(Bearing Wall FAQ revised March 12, 2003)
-- J.S.
You have to figure out everythinh Fasteddie said first. For the arch you need the width and desired height to figure the radius.
call a contractor ...
U are in over your head.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
I'll almost agree with the post that said you are in over your head... but then i'm still dumb enough to think MOST (not all... i quit think'n that) people can do most things if they do the research read up... study the situation... and do things in the natural order of things....
first thing... Get the newest issue of FHB... there is an artical in it that will keep you pretty safe.... and NO, a lap joint on a header is never a good thing... think of a header as a bridge and ask if you'd want to drive on a lap jointed one....
as for the arch.... again not a hard thing... but you need a few skills...
you need to have and be able to operate a recip saw, a skill saw, a jigsaw (for the way i do an arch)...a good level... drywall tools and the skill to use em...
in a clean room with no problems (no such thing as no problems) to demo frame, hang drywall and 1st coat of mud... for one guy thats a good full day... min of 2-3 more trips to mud feather in and sand... I don't know where you are but I'd guess you'd be looking at $1800 to $2500 without the paint and thats no trim...
materials... WAG $200
so you could save up to $2300... enought to buy the tools you'd need if you don't have em....just try'n to inspire you... chances are even if you screw it up... won't cost you alot more to get someone to fix it, as long as everything thats up stays up...
p
Okay - my favorite way to make an simple arch, after all the structural issues are worked out (see above).
Hang the top horizontal pieces of drywall on both sides of the wall opening, attaching the top edge to the top plate, header, trimmers, or whatever - the bottom half or so will hang, unsupported. Make two marks on the floor, )or on a raised stand, depending on the curvature you want) in the center of the width of the opening, in the plane of each side of the wall.
Figure the height of the center of the arch - say 7-1/2 feet. Make a stick that long, tape a pencil to the top, pivot it on the mark on the floor, and draw arcs on both sides of the wall on the new hanging rock.
Carefully saw that curve out on both sides, right on the line.
Cut a couple of dozen 2x4 or 2x6 blocks as long as the thickness of the wall inside the sheetrock (3-1/2"?).
Screw them almost edge to edge between the pieces of drywall, lined up with the cut curve, making dozens of little facets.
Now, cut a strip of drywall longer than you think you'll need for the curve of the arch, and as wide as the entire wall is thick (4-1/2"?).
Dampen the BACK of the strip, and let it sit for a few minutes.
With a helper, start at one end, and bend and screw the strip to the faces of your facet blocks.
Get the vinyl arch corner bead (square or bullnose), and "fair" the curve carefully with drywall nails or 6p box nails into all the blocks. The taping knife will actually ride on these ridges when mudding the curve of the arch, so it's important they are perfect.
Viola!
If you want to get fancy, you can do ellipses, four-centered arches, etc. just depinging on your drawing ability. For anything where I can't just swing arcs, I'll draw the curve in AutoCAD, then dimension it on a 1 inch grid and make points on the wall to connect.
I've done these from 24" to 16' wide, 4-1/2" to 40" thick (with metal strapping to support the 2x4x47" blocking from the ceiling), and never had a crack or complaint. I've done one over a double shower, pierced with a skylight shaft running up 2 storeys.
Forrest
Thanks for sharing your simple method of building arches. I would have expected that the curved drywall would have been done with two layers of 3/8" material, but it sounds like you are getting a lot more curvature than I expected out of 1/2" gyp board. What is the tightest radius you have found practical with 1/2" material?When an ellipse is the desired shape, do you tie your pencil to a loop of string or wire strung over two nails in a board fastened across the opening at the desired starting height of the arch?BruceT
> When an ellipse is the desired shape, do you tie your pencil to a loop of string or wire strung over two nails ....
You tie the ends of the string to two nails, and pull the middle of it out tight using the pencil. Keeping the string tight and running the pencil around as far as you need will draw half an ellipse.
The length of the string is always equal to the width of the arch. Put another temporary nail where you want the midpoint of the top of the arch, hang the middle of the string on it, and put the two end of string nails on the horizontal line where you want the curvature of the ellipse to start.
If you have a router with a nice round body, you can use a stronger string and guide it instead of the pencil, cutting in one operation rather than trying to follow a pencil line. Probably not a mathematically perfect ellipse, but a nice looking curve whatever it is.
-- J.S.
That is an elegant solution! I wouldn't be surprised if my Rotozip could be guided on such a string. String length would then be width of opening plus half circumference of Rotozip?BruceT
Be careful that there's no stretch in the string.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
What, you don't like bungee-router guides?BruceT
> String length would then be width of opening plus half circumference of Rotozip?
Start with a nail in the center of the base line. Tie one end of the string to it, place the rotozip at the end of the line, and pull the string around the router and back to the nail. Tie a Magnus hitch around the standing part of the string and adjust it to get the exact length you need.
Place the rotozip at the top point of the arch, and stretch the string over it and down so that both ends come to the same point on the plumb line right thru the middle of the arch. Hold the string to the rotozip, and move the ends with their nails to the horizontal base line. Nail off, and double check that you hit the endpoints and top point correctly. Tweak if needed, and you're good to go.
-- J.S.
lets assume you have the header sitition taken care of,heres how i do a arch,the first arch i did i had enough wood in it to have built another ark,just keep in mind your header is holding the weight,the arch is for looks.take 2- 2x4's about 10"[you can very this depending on how much arch you want] long and nail 1 to each side of the jamb,against the header,kinda like 2 short legs at the top of opening.get some masonite and rip it 3.5" wide and about 8' long for a 6' opening. now place one end on the bottom of your leg and arch it up to the header ,then mark it where it hits the other leg and cut to length. put it in place and nail it at each leg and at the header in the center. if you want cut a couple little short 2x4s and nail midway in each side of arch. when done it should be a pretty smooth arch. then cut another pc of masonite the same way and overlay the 1st one. you should have a nice smooth radius. then get a pc of 1/2 sheetrock,i usally wet it a little so it will bend and screw it up. then do the walls.once you do this you will find that you can do a arch in about 20 mins and be ready for sheetrock. good luck larry
hand me the chainsaw, i need to trim the casing just a hair.
Over time I have tried to discover all the easy ways to do things, and I am still learning. Once an opening is structurally sound, I simply take the measurements and go to my local architectural foam supplier and give him the measurements.
He then takes these measurements and puts them in the CAD machine and starts letting the CAD machine draw up an arch element that will fit my framed and drywalled opening. The CAD machine will then allow us to see on the screen an arch element that will fit into the drywall framed space with a perfect radius or eliptical shaped arch.
I then tell them what type of bullnose I need on specified edges.......square, two inch radius etc and how thick the wall material is. I can generally pick up my foam arch the next day and install it in the drywalled opening in about ten minutes. Then it is just a matter of taping and mudding and finish work. I try to do them this way as often as I can as it is such a time saver, especialy when doing arches in walls of varying thicknesses.
Mike Williams
That's a new one to me. High density foam like the blue insulation board? How well does it hold up to dings?
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Mike, not sure I got this one. Do you skim mud directly on the foam? What kind of foam?
DG/Builder
Here in southern california we use architectural foam a LOT for a variety of visual elements on commercial and private building projects. For instance, crown molding is an excellent example. Lets say that specs call for a large complex crown molding shape that is going to be 14 inches high and extend almost a foot out from the wall that will ring the ceiling of a movie theatre.
We simply take the specs to our foam guy, he draws up the pattern on the CAD.......has the machine cut out a four foot long sample and then we coat it, maybe even paint it, and have the client sign the approval and then call in our order to the foam guy.
In residential work the foam profiles, and arch inserts are much smaller and don't weign as much so we generally just attach them with a good stiff mix of 90 minute EZ sand drywall mud. Once set, we skim a coat of EZ sand over the surface of the foam and can then finish up with easy sand or regular dry wall mud. Obviously we are limited as we can not achieve a stain grade finish with foam, but most of the jobs we do this way are with very high ceilings and complex shapes and curves that would require a real craftsman to accomplish with wood, whereas any idiot (including me) can glue up a finished profile and then add enough layers of mud to finish it off nicely.
For all of us who have dealt with cutting wood crown upside down etc on a chop saw, it was a real learning experience for me to find that the only tool I needed was a good stiff hand saw. You simply cut it to length, put up the piece with push pins, hand saw the next piece and so on until the ceiling in 'crowned'. If the client wants elegant round corners in his crown molding instead of square, the foam shop will make the round corners for you out of the same profile. If you forget to order them, just take a piece of the crown on site, back kerf it with your trusty hand saw, put several strips of tape on the front of the foam and then bend it into the radius to fit the corner.
No need to worry about joints opening up in the profile or the ends as foam does not swell or shrink like wood. It takes a bit of work to make the crown look perfectly smooth with succesive coats of drywall and sanding, but once it is done.......no call backs as foam does not open up or split or do any of things that wood can and will do.
We also do a lot of this same type of foam work on the outside of commercial or residential construction except that we use special cement based products and mesh to protect and strenthen the surface coating.
Think of foam as simply taking the place of having to do an armature of 2x4's and paper and lathing in order to do a three coat plaster job. If you don't have a foam shop in your area, I recall seeing quite a few on the net that offer quite a stock selection and will custom cut for a nominal fee. The shipping costs on foam is very reasonable as it is so light. The time savings are enormous and it is easier for me to order and install complex foam shapes than to find a real craftsman (the guy we all admire with awe) who can do the same thing in wood.
Mike
Mike, I know all that. We do foam all the time for complex moldings and other stuff that never gets touched. And exterior synthetic stucco. But for a simple shape like a flat arch in a place that can get banged up all the time, I don't see it. I bet we can do a ply and bent drywall arch in less time than it takes for a guy to drive to the foam shop and back. And it's a lot more durable.
Still haven't told me what kind of foam you would use. Any foam we use with a mud skim coat wouldn't be durable enough for an archway. Unless you put half inch of mud on it, which makes no sense.
DG/Builder
I use that 90 minute EZ sand for the first coat or two than finish it up with all purpose drywall mud if it needs a really smooth surface. You are absolutely right about the fact that it will definitely not hold up to much impact damage. Smacking it with a tall piece of furniture that you are carrying will definitely tear it up, which is why I tell people to only do this in 'no touch' areas that are high enough not to be subject to accidental damage.
Mike
Frame the opening square, and about 6 inches taller than the high point of the arch, arches are typically built with 2 pieces of plywood, with short blocks in between. Ex. if your framing an arched opening for a 2x6 wall, lay out the radius on one sheet of ply, gang both sheets together and make one cut, (cutting both sheets at once) the outside dimensions of your ply will match your rough opening, minus a 1/4" or so. if your using 7/16" ply, than your criple blocks will be about 4 9/16" (7/16" x 2 = 7/8" minus 5 1/2" = 4 5/8" plus a 1/16" for variance. space your criple blocks in the radius section about 4"- 6" apart or so, so that the drywall has something to conform to. This is assuming that you've tackled the load bearing wall issue, if not, call a remodeling contractor.
Edited 1/29/2006 11:41 pm ET by tandttravis