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Wednesday, 27 June 2018 09:09

Fitting External Door's

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A quick guide to fitting a external door



When trimming a door to fit, 12mm can be removed from each edge of the door to a maximum reduction of 24mm in both the height and width. Any reduction must be removed evenly from each edge of the door, e.g. to trim your door by 8mm in width, remove 4mm off each side. External doors must have a weatherbar or rain deflector fitted to ensure that water runs away from the face and bottom edge of the door. Stable doors require a weatherbar fitting to both leafs. A drip bead should be fitted to prevent moisture ingress to the top edge of the door, e.g. fitted to the door frame head. Three hinges should be used to hang the door. Stable doors require 4 hinges and a weatherseal fitted between the 2 leafs. All hardware screw holes should be pre-drilled to prevent splitting of the timber. Locks should not be fitted adjacent to door mid-rails where the joint may be compromised. We recommend letter box cut outs are not made through vertical panels as this could lead to moisture ingress and/or failure of the product. Some glass styles are smooth on one side and obscure on the other: Please check that the obscure glazed faces of multiple doors are orientated in the same direction, e.g. if installing 2 glazed doors side by side. In areas of severe exposure, external doors should be protected by a canopy or porch in addition to recommended finishing. Sidelights are supplied with separate instructions for fitting/trimming.




Bare timber doors will require a light sanding prior to finishing. Take care when finishing glazed doors to ensure that the finish does not go on the glass. Secondary protection such as masking tape may be necessary. All timber surfaces must be given a total of three coats of high performance wood-stain or paint. It is important to apply the treatment to the door before final installation. When applying the finish pay particular attention to sealing the timber end grain on the tops and bottoms of the doors and any grooved areas within the door design: It is recommended that 2 coats of an end grain sealant are used on the top and bottom edges of the door prior to final finishing of the door. Ensure that all lock, letterbox and hinge cut-outs are also finished to the same degree as visible surfaces. Failure to treat all the timber surfaces may lead to excessive changes in moisture content which will cause the timber to shrink or swell, possibly causing splits and distortion. Clear translucent coatings are not recommended as the timber may discolour through UV degradation.


Pre-Finishing Summary




  • Use a ‘High Build’ tinted wood-stain or good quality exterior paint
  • Apply a minimum of 3 coats to all faces and edges (in severe exposure conditions apply extra coats)
  • Apply the same number of coats equally to the face, edge, lock, letterbox and hinge cut-outs
  • Apply at least 1 coat immediately upon unpacking the door
  • Check that paint or stain manufacturers’ product is suitable for veneered / engineered doors.





  • Use thin penetrating seals, oils, wax, dyes, preservatives or hard, brittle varnish finishes
  • Apply stains or paints in damp / wet weather
  • Use thinned / mixed paints or stains
  • Mix incompatible products, e.g. paint on one door face and stain on the opposite face.
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