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Technical Details

We often get asked questions about a number of aspects of purchasing a door. We have compilied a list of some of the most common questions below.

  1. How can I compare imperial and metric door sizes?
  2. What is the difference between Dowelled and Mortice & Tenon construction?
  3. What is the difference between a solid and engineered construction door?
  4. How much can I trim off my door?
  5. How should I finish my door?
  6. The glass has broken in my door, can this be replaced?
  7. What is the thickness of glass?
  8. My obscure glazed door has clear patches on the glass, what can I do to rectify this?
  9. What is the fire rating of my door?

Q1. How can I compare imperial and metric door sizes?

All dimensions are stated Height x Width

Internal Doors

mmInchesFeet & Inches
1981 x 457 x 35mm 78" x 18" 6' 6" x 1' 6"
1981 x 533 x 35mm 78" x 21" 6' 6" x 1' 9"
1981 x 610 x 35mm 78" x 24" 6' 6" x 2'
1981 x 686 x 35mm 78" x 27" 6' 6" x 2' 3"
1981 x 711 x 35mm 78" x 28" 6' 6" x 2' 4"
1981 x 762 x 35mm 78" x 30" 6' 6" x 2' 6"
2032 x 813 x 35mm 80" x 32" 6' 8" x 2' 8"
1981 x 838 x 35mm 78" x 33" 6' 6" x 2' 9"
2032 x 813 x 40mm 80" x 32" 6' 8" x 2' 8" 
2082 x 836 x 40mm 82" x 64" 6' 10" x 2' 10" 
2133 x 914 x 40mm 84" x 36" 7' x 3'
2040 x 526 x 40mm 80 1/4" x 20 5/8" 6' 8" x 1' 8 5/8" 
2040 x 626 x 40mm 80 1/4" x 24 5/8" 6' 8" x 2' 0 5/8" 
2040 x 726 x 40mm 80 1/4" x 28 5/8" 6' 8" x 2' 4 5/8" 
2040 x 826 x 40mm 80 1/4" x 32 5/8" 6' 8" x 2' 8 5/8" 
2040 x 926 x 40mm 80 1/4" x 36 5/8" 6' 8" x 3' 0 5/8"

External Doors

mmInchesFeet & Inches
1981 x 762 x 44mm

78" x 30"

6' 6" x 2' 6"
2032 x 813 x 44mm 80" x 32" 6' 8" x 2' 8"
1981 x 838 x 44mm 78" x 33" 6' 6" x 2' 9"
2082 x 864 x 44 mm 82" x 34" 6' 10" x 2' 10"
2134 x 915 x 44mm 84" x 36" 7' x 3'

Q2. What is the difference between Dowelled and Mortice & Tenon construction?

All our doors have either Dowelled or Mortice & Tenon joint constructions. Our Dowelled doors have joints held together by fluted dowels and adhesive. A Mortice & Tenon door has joints that are held together using traditional Mortice & Tenon joints and adhesive. Both methods delivery strong joints and ensure the doors have a long and durable life.

Q3. What is the difference between a solid and engineered construction door?

A solid timber construction door is, as it says, made from solid sections of timber; be it Oak, Hardwood or Pine. Engineered construction doors use a mixture of timber components including laminated Timber, MDF or Particleboard to form the main structure of the door. A real wood veneer is then applied to the door, usually 0.6mm thick, to give the door the final quanlity appearance you see.

All doors listed on Leader Doors.co.uk are of engineered construction (unless otherwise stated), as this gives greater stability and performance over a solid construction door. In the interest of continual improvement, efficiency and environmental awareness, the door manufacturers reserve the right to include engineered components in there doors.

Q4. How much can I trim off my door?

We often get aksed how much a door can be trimmed down by, below is a guide to the MAXIMUM thresholds for trimming doors.

Internal Real Wood Doors

For any door marked WoodDoor+ it is advised the no more than 6mm be trimmed from any side, top or bottom of the door. Should this occur the Warranty will be rendered invalid.

For any door marked XL it is advised the no more than 6mm be trimmed from any side, top or bottom of the door. Should this occur the Warranty will be rendered invalid.

For any door marked LPD it is advised the no more than 3mm be trimmed from any side, top or bottom of the door. Should this occur the Warranty will be rendered invalid.

Internal Pine & White Moulded Doors

It is advised the no more than 3mm be trimmed from any side, top or bottom of the door. Should this occur the Warranty will be rendered invalid.

Internal Fire Doors

We strongly advise following the manufacturer's recommendations supplied with the door, due to the fact that in a lot of cases if you reduce a fire door it will lose its fire rating.

FD30 (30 minutes) fire doors are usually 45mm thick, as opposed to the standard door thickness of 35 mm, FD60 (60 minute) fire doors most commonly used in commercial settings are normally 54mm thick. Specially constructed fire doors can have a rating of 4 hours or more.

Most fire doors have a solid core construction which can include: particleboard, chipboard, flaxboard and solid timber. The assembly of a fire door can vary greatly, some have: a timber framing around the core with a laminated veneer; others have a lipping (5-20mm thick) around the core with a veneer on top; and in some cases a plywood, veneer or MDF facing is glued on to the core without framing or lippings. There is no preferred construction method, as long as the desired fire rating is achieved. Please be advised that this is a general assessment and the products may vary for each different brand.

External Real Wood Doors

It is advised the no more than 6mm be trimmed from any side, top or bottom of the door. Should this occur the Warranty will be rendered invalid. It is advised that you purchase a door that is closest to the required width, even if the height is more, as you are able to reduce the height more than the width without affecting the integrity of the door. However, as with all our doors the warrenty is invalidated if more than 12mm is trimmed of the door.

Q5. How should I finish my door? 

For all doors we recommend the following guidelines for finishing your door. If you would like to paint your door we recommend a coat of primer or undercoat and then at least 3 coats of your chosen topcoat. If you would like to apply a stain to your internal door you should apply at least 3 coats of a good quality water based internal stain/lacquer.

Q6. The glass has broken in my door, can this be replaced?

Our glazed doors are manufactured in a way that the door is built around the glass and therefore there are no loose beads  that can be removed to take out the glazing. Unfortunately we cannot provide replacement glass.

Q7. What is the thickness of glass?

  • Flat Glass: 4mm approx
  • Bevelled Glass: 6mm approx
  • Double Glazed: 14mm approx
  • Tripled Glazed: 18mm approx

Q8. My obscure glazed door has clear patches on the glass, what can I do to rectify this?

Clear patches on obscure glass are usually a result of the construction process of a door and is caused by a silicone or adhesive "filling in" the glass etching. This can usually be removed by applying a small amount of white sprits and rubbing of the transparent patch. Leave the affected area to dry and the glass should return to an obscure state.

Q9. What is the fire rating of my door?

Only specific fire doors have a fire rating, this is 30 minutes.

Door Aftercare Information 

1. Doors must be kept and stored dry and flat.

2. Doors must be correctly treated prior to hanging, it is most important that flat top and bottom edges are completely and fully treated before the door is hung. Both faces and all four edges, and any “cut out” such as a letter boxes locks etc, require full treatment. This also includes removing any Paint & Peel system that is designed to protect the glazing. It is vital that the “End” grain is completely protected as this is where moisture can most easily penetrate causing swelling, splitting and warping.

3. Doors should be reduced in size equally from both sides when fitting. Mortice locks fitted at rail joints can result in removal of one or more dowels, so weakening the joint. The Mortice lock cavity should be kept to a minimum size and not fitted at rail joint.

4. Usually 5 coats of proprietary branded paint/polish/stain should be satisfactory but you should treat the door in accordance with the paint/polish/stain manufacturer’s instructions.

5. Timber is a natural grown produce subject to change in variations of humidity and temperature. We try to ensure that the timber has been prepared to make it suitable; however, we cannot know all the circumstances surrounding every situation in which our products are stored and installed. We cannot therefore give any guarantee against shrinkage, warping or splitting.

6. Regular maintenance of External doors should be maintained to prevent breakdown of any treatment and so protect the wood from deterioration.