There are lots of methods of surveying doors. I have listed some of the methods and procedures that I have used to survey and to train surveyors to be able to carry out a door survey succesfuuly.

Hopefully if you are struggling with the survey side of things you may pick up some handy pointers from this article 

What is the surveyor’s key role?

a)      To clarify the sales contract and the customer’s expectations and design and measure the door accordingly, to fit the purpose and application of the door product.

b)      To obtain customer confirmation of any details where the customer can exercise choice.

c)       To clarify any contractual issues with the customer.

d)      To ensure all surveyed product designs will conform to statutory requirements.

e)      To document concise information to allow the manufacturing and installation process to be undertaken successfully and efficiently.

f)       To prepare a schedule of all consumable materials and architraves required to complete a successful installation

The survey process,

If you want your surveyors to excel you need to make sure they are product trained and have all the relevant technical data, don’t expect them to guess, it is costly when they get it wrong. Don’t blame the surveyor if you haven’t provided the technical information or training.

A little bit of time and effort ensuring they are trained and have all the relevant information will be time and money well invested.

The survey is relatively simple process provided your surveyor has all the technical data from the door manufacturer you use, and is trained correctly.

Technical Information required

  1. Outer frame colours (internal and external)
  2. Slab colours slabs or panel colours (internal and external) remembering some manufacturers only manufacture slab colours outside white inside on certain designs.
  3. Maximum and minimum manufacturing parameters.
  4. Door and side screen slab or panel designs.
  5. Applicable glass designs for the specific slabs or panels.
  6. Applicable pattern backing glass available.
  7. Outer frame sizes.
  8. Compatible outer frame packers or add on sizes.
  9. Hinge types and colours.
  10. Hinge clearances.
  11. External cill sizes (depths and heights)
  12. Available threshold options sizes and heights and colours.
  13. Coupling jointer types available and sizes.
  14. Door Knocker designs and colours available.
  15. Kicker plate options and colours.
  16. Weather drip options and colours.
  17. Available door lock options.
  18. Door handle options and colours.
  19. Letter plates, door knocker designs and colours.
  20. Slab or panel Core construction including raised moulding sizes.

Before you measure anything

1)      Take Photographs of the existing door recording any existing structural or cosmetic  damage external & internal  before you take any measurements

2)      Always view from outside and draw your survey viewed from outside before you take any measurements

3)      Record the opening in or out of the door before you take any measurements

4)      Record the handing of the door hinged left or right before you take any measurements

The measuring process

1)      Check the cill for level and allow for out of level situations in the height to be able to level up the new door and cill

Survey errors occur here when the new cill packed up level and the door is then to tall for the opening or the door leaf is to tight to the internal head.

2)      Check both reveals in and out for plumb.

 Openings can be totally out of plumb on opposite reveals not allowing the frame to be fitted in wind leaving different reveal margins externally and internally, or not allowing the door sash to close in wind with the outer frame.

3)      Take 3 width measurements top, middle and bottom internal and external using the narrowest size to determine the width.

You need to take the narrowest size remembering that if the frame is fitted between brick reveals you will need to allow a 10mm clearance for any frame expansion.

4)      Take 3 height measurements left, centre and right internal and external using the narrowest size to determine the width

Again you need to take the shortest size remembering that if the frame is fitted between a lintel and dpc, you will need to allow a 10mm gap at the head for any frame  expansion.

5)      Take the diagonals to check the square of the opening.

This will determine any additional deductions you may need to make to allow the frame to be fitted plumb and square between brick reveals plus any expansion deductions.

6)      Check and measure and plaster thickness differences between internal and external widths and the head.

This is common survey error when not checked and hinges get buried behind plaster lines or door leafs are behind plaster lines on the reveals or head. Heavy plaster thicknesses could necessitate the requirement of frame packers or add ons to give hinge or door leaf clearances.

7)      Check and measure any dado rails or skirting thicknesses and positions.

Again a common error where thick skirting or dado rails will foul the hinges or door leaf and could necessitate the requirement of frame extensions or add/clip ons to give hinge or door leaf clearances.

8)      Check and measure the floor level in relation to the external cill level.  Low thresholds should have a 10mm floor clearance.

Probably, the most common survey error especially when low pvc or low aluminium thresholds are used and the bottom of the door leaf will not clear the internal finished floor.

9)      Check the existing frame thickness and its position in relation to any cavities and dpc’s.

 Remove existing architraves to check if necessary.  If the frame is to be tucked behind any render check that it can be fitted into a cavity one side and then shuffled back into the opposite cavity and  you have enough clearance with the frame entering the reveals at an angle. You may need to call up any external cills with horn additions separately to the frame to do this ensuring existing building finishes are not compromised.

10)   Check on positions and of any power cables, telephone cables, alarm cables, door bell cables etc.

Telephone and door bell cables may need to be repositioned or notched around. Power cables may need to be disconnected for safety reasons. A quite common oversight is that alarm sensors should be re fitted by qualified alarm specialists or the customers insurance could be null and void if it failed after being worked on by unqualified persons. 

11)   Ensure you have complied with approved document N: Glazing – materials and protection in particular BS 6206 (shaded areas showing requirements for safety glass). Also note any energy rated glass that may be required.

Surveyors sometimes miss the safety glass on adjoining windows.

1)      Check the existence of any restrictions limiting the installation of PVC-U replacement frames should be checked, especially for listed buildings and / or buildings with special architectural or historic interest.

This can become very costly and sometimes only comes to light after installation and reinstatement of timber frames is required.

2)      Undertake a safety risk assessment of the proposed installation.

Record any restricted access, asbestos, height and access equipment, customer property protection, gas pipes electricity cables etc. The surveyor can be held legally responsible in the event of an accident.

Sample of typical Surveyors site notes form

A signed survey product confirmation should be obtained and contain all of the following

  • Internal and External frame colour
  • Internal or external Slab or panel colour
  • Cill and threshold type
  • Door Handing (hinge side position
  • Door opening in or out
  • Cill and threshold type
  • Mid rail heights
  • Glass design bevels, stains, lead or Georgian layouts.
  • Panel designs
  • Backing glass pattern
  • Lock type
  • Handle type and colour lever/ lever, lever/pad, split spindle, key less entry, remote. etc.
  • Letter plate and colour
  • Door knocker type and colour
  • Security chain and colour
  • Night latch and colour
  • Spy hole viewer and colour
  • Numerals and colour
  • Additional customer information
  • Customers should always be shown samples or brochures and sign to say they have seen the samples etc.
  • Confirmation that it is not a listed property or has any restrictions imposed.
  • Methods of payment and collection of payment

Do not leave site until you are 100% confident that you have acquired all the relevant information to achieve a successful manufacture and installation of the product surveyed.

As I said earlier if you only pick up on a few items it will help you on your way to being a succesful competent surveyor

  1. nige says:

    One more point i always double check for, will the new door sash fully open to 90degs . I`ve seen a fair few that catch vestibule walls or the house step when there `s a porch on the front. Upvc/composite door hinges most of the time open further out than wooden door butt hinges..
    I also fit a restrictor on all outward openers, for windy days…

    • Steve Williams says:

      Hi Nige,

      Thanks for your comments,

      You’re right, I’ve seen a few open in doors fitted in porches that have a step down from the house, where the doors have hit the step before they have opened to 90° and again door restrictors are a must on outward opening doors in particular conservatory French doors. Better to fit restrictors and cabin hooks than replace a door sash that has ripped off the frame or even damaged the frame or adjoining frames.

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