When doing a renovation or adding an extension, it often becomes necessary to replace a door and jamb or install a new one from scratch.
Jamb moulding components are available and DIY installation is a lot easier if you apply a few clever tricks to speed up the job.
If the walls are out of plumb or the floors aren’t level, you will need to correct these problems first or the door won’t open and shut properly. Once the jamb is secured in position, you may need to trim the door to size before cutting housings for the hinges and hanging the door.
Use a drill with a holesaw and spade bit to bore the holes for the lockset and latch, then finish by securing the architraves.
Pack the jamb
Instead of standing the doorjamb in position while you insert wedges behind the hinge side, secure shims in the door opening first.
Measure the width of the doorway opening to calculate the thickness of the shims you will need.
Usually the opening allows for a gap of about 10mm on each side of the doorjamb.
If the opening is extra wide, you can use smaller wedges by temporarily securing offcuts of 12mm plywood at each of the hinge locations, then adding wedges or shims to plumb the jamb.
Position the shims at the top and base hinge locations using a long spirit level, or a straightedge with a shorter level, then add the centre shims if a third hinge is needed.
Allow for flooring
New flooring always looks best if it fits neatly under the doorjamb, otherwise you’ll have to cut around the intricate shapes of both the stiles and the architraves.
Save yourself time and trouble by cutting off the base of the jamb before the flooring is installed.
Measure the thickness of the floor covering and calculate how long the stiles will need to be to clear it. If practical, use an offcut of the actual flooring as a spacer under each stile as you install it.
Plumb the opening
Doorway openings in stud walls that are out of plumb can make door installation problematic.
As long as the base of the wall isn’t locked in by flooring, the solution is simply to nudge the base plates on both sides of the opening back to plumb.
You will need to cut the nails securing the base plates using a reciprocating saw or oscillating tool, then move the walls into position using a sledgehammer.
TIP Once the walls are plumb, reattach the base plates to the joists by skew-screwing in place.
1. Check for plumb and if either side is more than about 7mm out of plumb, adjust the wall before you install the door.
2. Nudge the wall back to plumb using a sledgehammer, using offcuts of 90 x 45mm timber to protect the plasterboard.
House the hinges
Internal doors are usually fitted with two loose-pin butt hinges and external doors with three fixed-pin butt hinges.
To house the hinges, first mark their positions on the edge of the door, usually 100mm from the top and 150mm from the base, plus one in the centre for an external door.
Next position an open hinge at these marks, drawing a square line across each end of the hinge then marking the width and depth of the hinge housing required.
TIP Use a marking gauge to scribe the depth line on the door.
1. Make fluted cuts
Use a hammer and 25mm chisel to cut vertical lines 1mm inside the hinge outline. With the chisel’s bevel facing down, hold the handle at a 45º angle to make a series of close fluted cuts at each hinge housing.
Step 2. Pare out the waste
Turn the chisel so the bevel side is facing up and hold the blade about 50mm from the end. Apply firm, even pressure with the other hand to pare out the waste. Finish by trimming back the edges to the hinge outlines.
Step 3. Secure the hinges
Check that each hinge fits snugly, then drill pilot holes towards the back of the screw holes in the hinge so the screws will pull the hinge tight into the housing. Secure the hinges using the supplied screws.
Level the jamb
Old houses often have sloping floors, but even newer houses can settle in unexpected ways.
A floor that’s not quite level will make it difficult to get an even space between the top of the door and the jamb head.
The solution is to calculate how far out of level the floor is then trim the high-side stile to compensate.
TIP This is particularly important if the door is being installed over existing flooring, and the jambs have to fit tightly to the floor.
1. Position a spirit level across the opening and pack under one side until it shows level. Measure the gap to find how much you’ll need to trim.
2. Cut the stile on the high side by marking a cut line then trimming the timber using a Japanese-style pull saw or similar fine-tooth tool.
Trim the door
Securing a new door or replacing an old one often involves slightly reducing the height of the door to provide clearance over carpet or other flooring surfaces.
If only 5mm or less needs to be trimmed, this can easily be done by positioning the door on a pair of sawhorses and shaving down the base with a power planer or belt sander.
Sometimes the door is 10mm too long or more, in which case the fastest and easiest method to trim it is to remove the waste using a circular saw.
TIP Always seal the base of the door after trimming to length.
Step 1. Mark the cut line
Apply masking tape around the base of the door, wrapping over the cut line to minimise any timber breakout then use a combination square set to the required depth to mark the cut line on the tape.
Step 2. Set the blade depth
Release the saw’s base plate control lever then position the door on a pair of sawhorses and place the saw on the door, adjusting the base plate until the blade teeth will cut about 5mm deeper than the door thickness.
Step 3. Trim the edge
Attach the rip fence and check its alignment by starting the saw and advancing it just far enough to nick the edge. Adjust the fence if necessary then continue cutting. Remove the tape, sand lightly and seal the cut.
Hide the fasteners
Screws are better for securing the hinge jamb to the studs because nails can work loose. You can also replace a short hinge screw with a longer screw to reinforce the hinge-side stile if necessary.
To avoid having to use timber filler to hide nail or screw heads, simply drive the fastener through the hinge housing, offsetting it so it won’t obstruct the hinge screws.
Use self-drilling screws or drill pilot holes to make it easier to secure the jamb to the studs.
Even if the door and jamb have been installed with the utmost care, the house can settle over time and problems can creep in.
1. Free the leading edge of a door that catches in the jamb just as it’s about to close, by planing the edge of the latch side slightly off square. This will ensure that the edge that reaches the jamb first is slightly shorter than the edge that follows, enabling the door to swing freely into the jamb without catching.
2. Ensure proper latching on a door that is hitting the latch-side stop and preventing the bolt from engaging properly. The stop piece on a jamb is secured to the main part, unless the jamb is a one-piece design where the stop is formed by rebating a single piece of timber.
If the jamb has a separate stop, it can simply be tapped over with a hammer, or pried off and reinstalled in a better position. On a rebated jamb, trim the edge of the stop using a router with a straight cutting bit. Cut away the ends, where the router won’t reach, using a 25mm chisel.
Round the edges with 150 grit abrasive paper before painting.
Cut the jamb head and stiles to length, marking the stiles’ position on the head with at least 10mm clearance to the top of the door opening. Cut housings in the head then secure with screws. Test-fit the door in the jamb, and the jamb in the opening.
Mark the hinge positions on the stile and door edge then chisel out housings so the hinges fit neatly. Use a straightedge and spirit level to plumb the stile in the opening, packing with shims. Secure the shims with adhesive and brads behind the hinge positions.
Attach the hinge stile to the stud with 75mm x 10g screws or bullethead nails through the hinge housings. Pack under the latch stile until the head is level then position the door, wedging the latch stile for 2mm clearance all round. Secure the stile with screws.
Secure the hinges to the door then position it at 90º to the jamb. Use a pry bar to lift the door until the hinges align with the housings. Secure the top and base hinges using two screws only, check for smooth opening and closing then drive the remaining screws.
Use the supplied template to mark the position of the lockset and latch holes. Drill a 3mm pilot hole on the door face then use a 54mm holesaw to bore from one side until the twist bit exits. Finish boring the face hole from the other side to prevent breakout.
Use a 3mm twist bit to drill a pilot hole at the marked latch position into the lockset hole. Follow using a 25mm spade bit to drill the latch hole. On the edge of the door, mark around the latch plate and chisel out a rebate to accommodate it.
Slide the latch into the latch hole on the door edge until the latch plate is seated in the rebate, then slide the spindle through the latch. Attach the inside handle then slide the exterior cylinder assembly into position, securing with the supplied screws.
Close the door and mark where the latch bolt strikes the stile. Position the striker plate and mark around the inside and outside, then cut a rebate for the plate. Drill the centre hole deep enough to accommodate the latch bolt and secure the striker plate.
Cut the architraves to length, mitring the corners to 45º and setting them 5mm back from the inside edge of the jamb. Attach the architraves to the jamb using 40 x 1.6mm nails or a brad nailer, reinforcing the mitres with PVA adhesive and panel pins.