What's truss uplift?
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More how to install crown molding tips.
Cut the inside corner as you normally would. Mark the edge on the face of the molding with a pencil; this will serve as your coping-saw cut line. Hold a coping saw at a 5-degree angle away from the face of the molding and carefully cut along the marked edge. Check for a tight fit by bringing the molding to the wall and sliding it into place. If the coped edge doesn't exactly match the profile of the inside piece, use a wood rasp or utility knife to pare away excess wood.
How do I cope crown molding?
A couple of installing tricks for crown molding
Owner Tutorials installing crown tricks
Owner Tutorials - How to install crown moulding
What's truss uplift? / Crown molding installation tips / Coping Crown molding /
How to install crown the tips & tricks page
1. Determine which way the joists run, on the walls that are parallel to the crown you'll probably want to place a "backer" if you are using larger than 4 3/4 crown or cross nail into the ceiling the studs. If you use backer keep it 1/8 to 1/4" off of the spring angle and screw it into the top plates of the wall. Locate your studs & joists and mark them so you'll get good contact use 8d in the centers & 6d towards the ends under 3 1/2" crown you'll hit the two top plates
2. While you are up there finding the studs, use a marking gauge to mark out the bottom of the crown & the top every 6 ft or so. Measure the lengths and in large numbers write them on the walls behind the crown. For outside corners use your patterns to double check where the crown meets at the bottom to give you the best joint with your gauge block marks. Fine tune at install and make a note in that corner if it's off 90, inside corners also make a note if they are off of square.
3. Cope or not to cope... I'll leave that to you, I cope on larger crown and in new buildings. I glue the joints on the MDF crown that are smaller than the 4 3/4 I've never have much problem with them. On newer building with Trusses that were installed with higher than recomended moisture content you'll want to cope because of truss uplift (I'll explain that below) in that case you want to nail to a backer too rather into the trusses as noted before. Check for seasonal cracks at the ceiling & walls for evidence of uplift.
Truss uplift is a phenomenon common in newer homes built with roof trusses and is normally due to moisture differential between the bottom chords and the top chords of the trusses. The bottom chords of the truss is buried in heavy insulation (normally 10"). In the winter the warm air from the ceiling below and the thickness of the insulation keeps the bottom chord dry, causing them to shrink. While the top chords are absorbing moisture and being kept damp with the high humidity in the attic. The dampness of the top chords of the trusses cause them to expand. This differential movement in the top and bottom chord of the trusses causes them to arch up in the center. When the trusses arch up it causes cracks in the ceilings at the center of the building. As the trusses dry out with the warm summer air they drop back down closing most of the cracks.
4. When measuring for coped inside crown, use the marking gauge and measure from the lower point from wall to wall. When you have an outside corner you'll need to measure exact, but for inside coped measurements you'll want to add a small amount so that the crown snaps in tight on anything over 8 ft. Add about a 1/16 to 10' and 1/8 for even longer 12' + pieces.
5. When nailing the crown in place you start from the center and leave the ends loose until you get the next piece up. Once you've moved the crown into position at the joints then you'll nail out both corners. You'll find on older buildings, (even some new), it'll be handy to carry a few shims with you to hold the crown in postion.
6. If molding isn't long enough to span a wall, splice two pieces together with a scarf joint centered over a wall stud. To do so, set the miter saw to the right-hand 45-degree setting. Hold the first piece of molding to the right of the blade, so its back is tight to the fence, and cut. Hold the adjoining piece to the left of the blade, and cut. Pilot a hole in the overlapping molding, inch to the side of the joint, and attach with 6d finish nails or even better a finishing screw at the top of the scarf.
During
Before & After
Before & After
Before & After
Tools you'll need for coping at Amazon
You can use a jig saw but that is best left to the profesionals
This is the archived version of my Tutorial for the new site visit:
NEW TUTORIAL SITE
more information and the udates will be there: www.installcrown.com
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