Door and Window Frames

DOOR FRAMES

TYPES OF DOOR FRAMES

The door frame provides a secure attachment for the door. Depending on the type of door, its function, and its location, different types of door frames can be constructed. The most common door frame consists of three members (Fig. 1):

Two vertical members called posts (a)

One horizontal member called a head (b).

When it is necessary for the door to fit tightly in the frame, it consists of four members (Fig. 2):

Two posts (a)

One head (b)

One member on the floor, called the threshold (c).

When additional light or ventilation is needed for a room, a fanlight is added to the frame structure by adding one more member between the posts, called a transom (Fig. 3, d).

Note that since the threshold is in direct contact with the floor, or even partly embedded in the floor, it is in special danger from attack by termites or fungus (Reference Book, pages 141 to 144).

BEAD OR REBATE TYPE DOOR FRAMES:

Each of the above door frames can be made either with beads (Fig. 4) or a rebated construction (Fig. 5).

Beads are preferred over a rebate for two reasons: the construction is easier, and it is possible to adjust the beads after the door is hung. Beads are always fixed into place after the frame is installed and the door is hung.

Rebates, however, do have a better appearance than beads, and no extra wood is required to make a rebated frame.

JOINTS FOR DOOR FRAMES

JOINTS FOR DOOR FRAMES WITH BEADS:

The joints for a door frame made with beads can be common mortice and tenon joints for box-like constructions. They may be either pegged, wedged or nailed (Basic Knowledge, pages 104 to 106, and 124; also Drawing Book page 43 and pages 67 to 71).

If a transom is required, it should be installed using a stub tenon joint to prevent water from penetrating the mortice (Basic Knowledge, page 122).

If a threshold is installed, a common mortice and tenon joint is used for it, but wedges should not be used since they might fall out. Pegs cannot be used either, because the threshold is too thin. This joint should be nailed.

JOINTS FOR DOOR FRAMES WITH REBATES:

If the door frame is made with a rebate, take care that the shoulders of the tenons are set out and cut correctly. One shoulder of the tenon is cut longer to fit the rebate (Drawing Book, pages 67 & 68).

The thickness of the tenon is affected by the size of the rebate. If the rebate is 1/3rd or less of the width of the member, the tenon will not be reduced in size (Fig. 1). If the rebate is wider than 1/3rd of the member, the thickness of the tenon (and accordingly the mortice width) is reduced by the depth of the rebate (Fig. 2).

Besides these considerations, the construction of these joints will be the same as for any common mortice and tenon joints for box-like constructions.

HEADS OF DOOR FRAMES

HORNS: in order to provide an additional attachment to the wall, the ends of the head and the threshold can project beyond the posts into the wall. This is especially necessary in mud walls.

These projecting parts can be shaped like horns (Fig. 1), or else the front corners can be cut off at an angle (Fig. 2). These shapes give a good appearance to the frame head when the frame is built into the wall.

WEATHER STRIPS:

If a door frame is to be installed in an outside wall, you need to take some extra precautions to prevent water from entering between the lintel and the frame head, and between the door itself and the door frame.

Weather strips (Fig. 3) can be fixed on the door head to keep water out. We will learn more about weather strips later in the book, in the section on window frame heads.

STEEL CRAMPS:

These are pieces of mild steel rod which are fixed into the door posts (Fig. 1, Below). They are fixed about 60 cm apart; near the head, middle and foot of the frame.

The function of these cramps is to secure the frame rigidly to the blockwork. They are set in the posts in positions which correspond with the bedjoints of the blocks, so that they can be built into the bedjoints.

To fix the cramps in the door frame, drill holes in the posts. The holes should have a diameter a little smaller than the rods, and should not go all the way through the post. Bend one end of the rod to form a head (Fig. 2, above) and knock the head into the post. Bend the other end to a right angle so it fits into the cross joint between the blocks (Fig. 2, above ).

MEASUREMENTS FOR DOOR FRAMES

MEASUREMENTS OF THE TIMBERS:

Usually door frames are made of timbers which are about 10 cm wide and about 5 cm thick. If the posts are held in the wall by steel cramps, it is possible to reduce the size of the timbers to 7,5 by 5 cm. The cramps provide a good grip to the wall so the frame doesn't have a lot of stress on it. This means that the timbers can be made smaller and thus less costly. The cramps are made by cutting iron reinforcement rods.

The frame itself is always measured from inside face to inside face. Unless it is stated otherwise on the estimate, measurements given for door frames are always inside measurements.

MEASUREMENTS OF THE FRAME WITH RESPECT TO THE MASONRY:

To make the work easy, to avoid extra block-cutting, and to reduce waste, the outside measurements of the frames should correspond to the building unit measurement of the blocks used to construct the wall. For example:

- The building unit measurement for landcrete blocks is 31 cm wide by 24 cm high. The outside height of the door frame will be 8 x 24 = 192 cm.

The ouside width of the door frame will be 3 x 31, minus 2 cm for one cross joint =91 cm (Fig. 3),

The steel cramps are also placed according to the building unit measurement of the blocks, so that they will fit into the bedjoints of the wall (Fig. 3).

CONCRETE SHOE

In order to give a firm base to a door frame with no threshold, concrete "nlioes" can be fitted on the posts.

To make the shoes, drive steel dowels into the bottom end of each post before setting the frame in the wall (Fig. 1). The projecting ends of the dowels are eaclosed later by the finished floor and the shoe (Fig. 2).

Spacers are used to keep the frame at the correct height during the building operations (Fig. 3). The steel dowels are short pieces cut from reinforcement rods.

ADVANTAGES AND DISADVANTAGES OF THE THRESHOLD (Fig. 3):

advantages:

The door closes tightly into the framework.

If the threshold is thick enough, It can be made with a rebate.

disadvantages:

The threshold is easily attacked by wood diseases or termites.

More materials are needed.

More joints have to be made, therefore construction is more difficult.

Water can penet, ate between the threshold and the finished floor (Figs. 4a & 4b).

ADVANTAGES AND DISADVANTAGES OF THE CONCRETE SHOE

advantages:

The wood is not in direct contact with the floor, so there is less danger of attack by termites, etc. Less materials are needed. The shoe secures the doorframe to the floor.

disadvantages:

The door might not close as tightly as with a threshold. If the frame is not well braced during the building operations, there may be a danger of distorting it while fixing it in place.

MAKING A REBATED DOOR FRAME WITH A CONCRETE SHOE:

• a. Study the drawing.
• b. Prepare a cutting list.
• c. Select the wood.
• d. Plane the wood to the required sizes (as indicated on the cutting list).
• e. Make the face marks.
• f. Mark out the joints (take special care in marking out the shoulders of the tenons on the posts) and mark the length of the posts.
• g. Mortice the head and rip the tenons at tha posts.
• h. Plane the rebate.
• i. Cut the shoulders of the tenons.
• j. Drill the holes for the steel dowels.
• k. Clean up the inside edges.
• I. Paint all the members with a primer, especially the joints.
• m. Fix the steel dowels and the wooden spacers.
• n. Drill the holes and set anchors at the correct places (steel cramps).
• o. Assemble the frame with squaring strips.
• p. Cut the horns to the required shape and paint them.

Take care when marking the lengths of the posts. They should be the length of the door; plus the upper joint, and minus the height of the concrete shoe.

ASSEMBLING THE DOOR FRAME:

To keep the door frame rigid and square during the various building operations, it needs to be braced. This bracing is done with squaring strips (Fig. 1, last page). These strips are about 2x5 cm, and they are cut into the rebate or nailed to tla face of the frame. They hold the frame square and keep the correct distance between the posts.

The proper steps for assembJing a door frame are as follows:

• a. Knock the frame together.
• b. Place the frame, rebate side up, on the workbench.
• c. Clamp the posts to the head (use sash clamps ur the wedges on the bench).
• d. Nail a squaring strip to hold the posts at the correct distance apart.
• e. Test for squareness from corner to comor (diagonally).
• f. With the clamp still in position, fasten the joints.
• g. Cut and nail the other squaring strip diagonally from the head to the post (Fig. 1, last page). This holds the frame square.
• h. Cut the posts to the roquired length.
• i. Drill the holes for the steel dowels and fix them. They should be long enough to anchor into the concrete floor.
• j. Nail wooden spacers into the inside of the rebate. These keep the frame at the correct height during the building operations (Figs. 1 & 2, page 70).
• k. Finish off the frame. The priming coat of paint should be applied to the external woodwork before it is fixed in place.

When timber with a small section, for example 5 x 7 cm or 5 x 10 cm, is used for the posts, an extra squaring strip should be fixed horizontally in the middle of the frame. This prevents the pressure of the blockwork from distorting the frame.

INSTALLING DOOR FRAMES

Frames which are improperly built-in can cause problems later, when the plastering is done or the doors are hung. Therefore we must give special attention to setting the frames properly.

A door frame should be fixed in such a way that the door can open flat to the wall. Otherwise, the door will form a lever to the frame, and the hinges will be forced out when the door swings wide open suddenly.

Door frames can be fixed in position either during the masonry construction or after the walling has been completed.

SETTING FRAMES DURING MASONRY CONSTRUCTION:

The first frames to be set are those of the outside walls. When the masonry work has been built to floor level, the door frame is placed in position according to plan and at the correct height, and held there by means of wedges (Fig. 1, a, next page).

To hold the frame in position during the following building operations, we use struts. These are braced against blocks on the ground and lean up to the head of the frame, where they are secured with two nails (Fig. 1, b, and Fig. 2).

The masonry line is used to align the frame with the face of the wall. The line is fixed at the two corners of the wall and two small wooden blocks are used to hold the line out from the wall by the same amount as the thickness of the future render layer; so that the line shows the position of the face of the render on the finished building (Fig. 1, c).

The line should be free (not touching any frame or block) from corner to corner of the building. It should be separated from the frame faces by about a trowel's thickness (Fig. 3).

Because the posts are long, the plumb bob is the best tool for making sure that the frames are straight and upright. Hold the bob at the inside top of the frame, so it has room to swing freely (Fig. 1, d). Check both posts (Reference Book, page 5)

To adjust the frame, the wedges are knocked a bit in or out, thus raising or lowering one post at a time until the frame is straight.

The face of the frame can be plumbed at the same time. To do this, step to one side of the frame and sight the edges of the post and plumb line. A helper should stand by the struts and either "give" or "pull" them until the frame is straight. Take care that the space between the face of the frame and the mason line remains correct (Fig. 3).

As a final check, the soffit (underside) of the head can be levelled with a spirit level (Fig. 1, e).

- REMEMBER: Be sure that the face of the frame is in line with the mason line, not flush with the face of the blocks. When the building is finished, the render surface and the face of the frame should be flush.

Make sure that the frame remains at the correct height, so that the steel cramps can fit into the bedjoints and the frame does not get twisted,

After several courses of blocks have bean laid, the frame should be rechecked to make sure that it has not become distorted by the blocklaying. Blocks should be laid on both sides of the frame at the same time, so that it does not get pushed out of plumb.

The struts and braces are taken off only when the blockwork has reached the head of the frame.

If more than one framS is erected, walk around the building and look from a distance to compare the frames with each other and make sure that they are all in the correct alignment.

SETTING FRAMES AFTER THE WALLING HAS BEEN COMPLETED:

In this method, the installation of the frames is postponed until the roof construction is complete, in order to reduce the risk of damage to the woodwork from the rain and sun.

Hardwood or plastic plugs are driven into the bed-joints to serve as anchors for the frame. The frame is then put into position and nailed or screwed to the plugs.

WINDOW FRAMES

TYPES OF WINDOW FRAMES

The function of a window frame is to admit light and air into the building. The most common frame used is the solid window type, consisting of an outer frame into which a casement or louvres are fitted.

The most common window frame consists of four parts (Fig. 1):

Two posts (a)

One head (b)

One cill (c)

When additional light and ventilation are needed, a fanlight can be added. The extra piece is called a transom (Fig. 2, d).

If wider windows are required, a mullion (Fig. 3, e) can be added.

Any of these frames can be made with a rebate or with beads, or with a combination of the two (Figs. 4 & 5).

For a list of the advantages and disadvantages of beads or rebates, see the section on door frames. If beads are used, they are fixed after the casement is installed, so they can be adjusted.

MEASUREMENTS OF WINDOW FRAMES

Before you start constructing a window frame, you have to decide:

whether the window will have shutters, louvres or any other kind of closing;

If there will be any burglar proofing, and if so what kind;

if any mosquito proofing is required;

and where the window will be installed (does it have to be opened frequently, for example).

All these factors can influence the kind and sizes of timber we use, and the size of the frame itself.

REMEMBER: Window frame measurements which are given with no further explanation are always inside measurements.

MEASUREMENTS OF TIMBER SIZES FOR WINDOW FRAMES:

A very common size of timber used for window frames, is 7,5 to 10 cm wide, by about 5 cm thick. This size of timber is readily available and relatively inexpensive. If large frames are required, the timber size should be about 15 cm by 5 cm.

MEASUREMENTS WITH RESPECT TO THE CASEMENTS:

The height and width of the window frame aro partly determined by the kind of casements which will be used. If ready-made casements are used, the frame has to be the right size to fit them. If the casements are to be made, consider the timber sizes which are available and choose the size of the casements according to the size of the boards, to avoid waste.

MEASUREMENTS WITH RESPECT TO LOUVRES:

If glass louvres will be installed, their size will determine the height and width of the frame. Find out the size of the louvre first, then start making the frame, not the other way around. Mistakes here can be very expensive!

Also make sure that there is room enough to open and close the louvres and that the mosquito proofing, if present, does not interfere with them.

Louvre windows will be discussed thoroughly in one of the next lessons.

The type of burglar proofing which is chosen will also affect the construction of the window frame, and we will consider this in one of the later lessons.

STEEL CRAMPS

If steel cramps are used to hold the frames, they should be positioned to fit into the horizontal joints (bedjolnts) of the walls (see Measurements of Door Frames section, page 69).

JOINTS FOR WINDOW FRAMES

When you are marking out the joints, first decide whether the frame is to have a rebate or beads.

In general, the joints for window frames are the same as those for door frames (see the section on Joints for Door Frames, page 65).

MAKING A WINDOW FRAME WITH TRANSOM AND MULLION:

The joint for the transom-million connection should be a stub tenon, to prevent water from entering the mortice at the top. Take care when marking out and cutting the shoulder of the tenon where it meets the slope of the cill, so that they fit together exactly.

• a. Study the drawing.
• b. Prepare the cutting list.
• c. Select the timber.
• d. Cut the timber to size.
• e. Plane the timber to size and make the face marks.
• f. Mark out the joints. Take special care in marking out the shoulders of the joints. The head, transom, and cill must be marked out together, as the two posts and the mullion must also be marked out together.
• g. Mortice the head and cill, and make stopped mortices in posts and transom. h. Rip the tenons for the transom, posts and mullion.
• i. Rip the horns on the head and cill. j. Prepare the rebate and throating if required. k. Cut the shoulders of the tenons. 1. Smooth and clean up the inside edges.
• m. Paint the frame with a primer coat, especially at the joints.

ASSEMBLING THE WINDOW FRAME:

• a. Place the frame on the workbench, with the rebated side up.
• b. Fix the transom to the posts.
• c. Fix the mullion to the transom.
• d. Clamp the head and the cill to the posts and mullion.
• e. Test for squareness at the four corners, and check the diagonals.
• f. Cut and nail the squaring strips.
• g. With the clamps still in position, fasten the joints.
• h. Finish off the frame.

CILLS OF WINDOW FRAMES

The cill should have a slope on the outside, to keep rain out of the building. This slope can be constructed by chamfering the cill (Fig. 1) or by a combination of chamfering and rebating (Fig. 2).

It is important to prevent rainwater from entering the space between the cill and the wall, where it could cause the cill to rot. A throating at the soffit of the cill (Figs. 1 & 2, arrows) allows water to drip down instead of running back under the cill. The angle of the throating should be parallel to the slope of the cill.

Another way to keep water out is to fix a metal k.rip, called a drip, under the cill (Figs. 3a & 3b). The drip is fixed in a sawcut in the underside of the cill, so that the water which drips onto the metal will not run inwards. The slope of the metal comes to just inside the face line of the cill (Fig. 3b).

The metal strip should extend past the ends of the cill. If it does not, the water which runs down the posts of the frame will damage the render around this part at the corners of the frame.

It is also possible to combine the two solutions, by fixing a metal strip onto the throating.

Every cill should have some kind of protection to keep water from entering between the cill and wall. All cills must come out at least as far as the finish line of the render.

As an alternative to the wooden cill, the window can be constructed with a plaster cill. The posts are fitted with steel dowels and a concrete shoe. The construction is similar to that of a door frame with a concrete shoe (Fig. 4, also see Concrete Shoe).

HEADS OF WINDOW FRAMES

Some protection must also be added at the head of a window frame to prevent any water from entering the space between the head and the lintel and causing damage to the wood. The simplest method is to fix a metal strip similar to the one on the cill. The part of the strip which is plastered over should be bent slightly upwards to prevent water from entering (Fig. 1a, arrow)

Note that the line of nails is staggered so that the drip ( or weather strip) is firmly secured to the head (Fig. 1a). Otherwise, movement of the strip during heavy rains or storms would probably loosen the render.

These metal drips may be put on when the frame is set up, or left until just before the rendering is done.

An alternative method would be to fix wooden battens, shaped as shown in Fig. 2, on the face of the window head. This method gives a more satisfactory appearance to the window frame.

A combination of both these methods is also possible (Fig. 3).

The importance of fixing weather strips on both the cill and the head of the frame cannot be over-emphasized. They are easily overlooked during the construction of the building and one might be tempted to do a quick job and leave them out. But in the long run the strips will save money by preventing water damages to the wood and expensive repairs.

The same kind of protection can be applied to the heads of door frames.

The heads and cills of window frame t can be provided with horns to give an additional secure fixing to the wall (see Heads of Door Frames).

INSTALLING WINDOW FRAMES

Installing window frames is similar to installing door frames (see Door Frames section). A window frame should be fixed in such a way that the casement can open flat to the wall, otherwise the casement will forui a lever with the edge of the wall. This can cause the hinges to be forced out when the window is blown open by the wind.

Window frames can be installed either during the construction of the walls, or after the walling has been completed.

INSTALLING THE FRAMES DURING THE WALL CONSTRUCTION:

When the blockwork has reached window cill level, the frames can be set and aligned in the same way as a door frame. The chief difference is that in the window frame the horizontal members are usually longer than the vertical members, and for that reason more attention is given to levelling the head and cill of a window frame than to levelling the head of the door frame (Fig. 1).

If more than one frame is installed, check them by comparing from a distance to see if they are aligned, as with door frames.

INSTALLING THE FRAMES AFTER WALLING HAS BEEN COMPLETED:

This second method is not so commonly used, but It also has Its advantages. in order to keep the frames clean, square and dry, they are kept in a store ua+il the building is roofed. Openings are left in the blockwork to receive the frames, horns, and steel cramps. The frame is set into this opening and the steel cramps and horns are secured with mortar.

Sometimes hard wood or plastic plugs are used to secure the frame in the wall.

- NOTE: The window frame does not rest directly on the landcrete wall; this would provide a path for moisture to get into the landcrete and weaken or damage it. The window frame is set upon a bed of concrete or cement mortar (Fig. 1, A).

WALLING UP BETWEEN FRAMES

First mark the positions of the blocks on the outsides of the frames. Mark both the height of the blocks (Fig. 1, a) and the face line of the blockwork (Fig. 1, b). The face line of the blockwork will ha inside the face line of the frames, because the faces of the frames must be flush with the finish line of the render.

- NOTE: The window frame does not rest directly on the landcrete blocks. This is because moisture could enter between the cill and the landcrete and get into the blocks, where it would cause them to swell and fall apart. To protect the landcrete blocks, the cill must rest upon a bed of concrete which can be up to 10 cm thick. By adjusting the height of this concrete bed, the anchorage irons and the heads of the frames can be brought into alignment with the bed holding the blocks.

The first blocks laid are those which touch the frames. The courses in between are completed and aligned with th aid of either a straight edge, spirit level, or mason line, depending on the distance between the frames.

Pay special attention to the anchorage irons of the [[[ . r~ .i]]]]. Make sure that they are not just embedded in the bed joint; instead make grooves to the faces of both blocks, which can be filled with mortar to anchor the iron and to protect from rust (Fig. 2),

MOSQUITO PROOFING

It is often necossary to install mosquito wire on doors and windows. The wire screen is normally attached with wooden beads directly onto the window frame. For louvred windows it is fixed on the outside. For casement windows which open outwards, the wire screen has to be attached on the inside or onto s separate framework which is hinged onto the inside of the frame.

A separate framework for the mosquito wire is commonly constructed on doors. Make this framework like a panelled door (this door and its construction are described in one of the other sections, under Doors). Use one or two braces in the framework to keep the door rigid. Often a spring is attached to the wire door to keep it in the closed position.

BURGLAR PROOFING

It i3 practically impossible to keep burglars out of a house when the occupants are away, but it is at least possible to make the house burglar proof to the extent that burglars cannot enter without making considerable noise and so alerting people in the area.

TYPES OF BURGLAR PROOFING FOR WINDOWS

One of the most common methods is to fix mesh wire or expanded metal directly onto the frame, in a way that it cannot be torn off without making considerable noise or using a special cutting tool. Use strong beads to attach the wire to the frame and plenty of screws or nails (Fig. 1).

Sometimes burglar proofing is made from welded iron rods in different patterns and fixed directly into the wall around the window. It should be anchored well and deeply enough so that it cannot be pulled out (Figs. 2 & 2a).

Another way to make a window safer is to fix Iron bars horizontally into the frame. This must bo done during the assembly of die frame. If some of the bars stick out at the sides of the frame, they can also be used as an additional anchor for the frame in the wall (Fig. 3). If the span between the posts of the window is large, the horizontal bars may need to be reinforced by having vertical bars welded nto them, so that they cannot be bent up or down to allow the burglar to enter.

The bars can also be applied to windows fitted with louvres. in that case, the iroo bars are placed between the louvre glasses (Fig. 3a). They must be placed in such a way that they will not obstruct the louvres when they are opened.

A relatively inexpensive and reliable burglar proofing is the wooden type. During assembly of the frame, this burglar proofing is installed into mortices made in the head, cill and posts of the frame. The separate pieces are fitted together with halving joints in a crosswise pattern (Fig. 4).

If outward-opening casements are installed in a frame, install the burglar proofing on the inside face of the frame. Leave a small opening in the burglar proofing for the hand to pass through in order to open and close the window.

For louvred windows the burglar proofing is always installed on the outside.