Wooden Interior doors

standard sizes - panel doors - hollow doors - glazed doors
imperial/metric equivalents

Two basic features define internal doors:

• Height, width and thickness
• Method of construction

Doors come in a number of standard sizes:

• Width - 24, 28, 30, 32, 34, 36 inches (each designed to fit openings between 1/4 inch less to 5/8 inch greater)
• Height - 78, 80, 82 inch
• Thickness - 1 3/8, 1 3/4 and 2 inch
  For a replacement door, the correct thickness should be chosen to avoid the need to reposition the door stop strips.

Method of door construction:

Panel door

These are made from pieces of solid timber, the stiles and rails being fixed together either by mortise and tenor joints (with wedges) or by dowels. The number of panels may vary, but the general construction is similar with full height stiles on each side with top, middle and bottom rails.

The bottom rail is wider than the top rail, and the middle is normally below the mid point - so it is easy to tell which way is up.

With the solid timber stiles and rails, these doors can be trimmed fairly easily to fit an existing door frame They must not be excessively trimmed as there is a risk that the sides of the mortise may be exposed in the top/bottom rails or the wedges holding the joints in the stiles becoming weakened.

Hollow Doors

These are made using a hidden frame covered with a thin cladding on each face and, normally, solid timber strips down the two edges to give a decorative finish. The cladding may be ordinary hardboard, which can be painted after the door has been hung, or a decorative plywood that can be varnished to give a natural timber appearance.

A number of different types of 'in-fill' within the door are available to give the faces some strength and rigidity. The simplest form of in fill, is a cardboard honeycomb, other specialist in-fills are used to make the door fire resistant.

Within the door, a solid timber area is provided for fixing the lock and handle; this solid timber is normally restricted to one side of the door and set at a suitable height for the lock/handle. So when hanging a door, it must be hung the correct way up and with the correct side to the hinge - failure to do this will mean that there will be nothing solid within the door where the lock/handles will need to be fitted.

Hollow doors cannot really be trimmed (either in height or width) to fit an undersized door frame; this generally means that these doors can only be hung in modern houses where 'standard' door frames are fitted.

Glazed Doors

Glazed doors are ideal where it is desirable to 'borrow' light into a dark area such as a passage.

These doors are made with solid timber surround and may be half glazed, full glazed or 2 half glazed.

The frame is normally made from solid timber in the same way as for panel doors with the inner edges of the stiles and rails machined to take the glazing. The stiles and upper/lower rails can be trimmed as for a panel door.

The important aspect is the type of glass used to glazed the door. UK regulations require that Safety glass is used in full glazed and lower glazed panels; it is always wise to use Safety glass for all glazing in a glazed door. Safety glass cannot be purchased off the shelf, it is in fact ordinary float glass which has been subjected to a special heat treatment - the glass must be cut to size before it is treated.

Imperial/metric door equivalents

standard sizes - panel doors - hollow doors - glazed doors