Installation and Finishing Guidelines for External and Internal Doors

Please contact us to arrange your appointment, to discuss your project with one of our door and window specialists. Thank you for your continued support.

 We highly recommend you use an experienced carpenter / door fitter / decorator to carry out the door measuring, installation and finishing and that theses guidelines are followed:

Installation Guidelines for External Doors

Measuring the opening width at top, middle and bottom will ensure you notice any variance in width which must be considered when choosing which size to order.  For the height you must measure from the top of the threshold, step or flooring the underside of the frame.  In both width and height, you must then deduct a small allowance so once fitted the door will not scrape the frame or the flooring.
You will need to trim the door to suit.  Please ask us for advice if you are not sure which size of door is best.
If measuring and installing a door and frame the structural opening must be measured in both height and width. 
When trimming a door to fit, either 8mm or 12mm can be removed from each edge of the door to a maximum reduction of 16mm or 24mm respectively for both the height and width.  The amount depends on the factory or origin.  Please check with us to confirm.  Taking more than the maximum from the edge of a door can weaken or damage the door and will go against the guarantee. 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 weather bar or rain deflector fitted to ensure that water runs away from the face and bottom edge of the door. Stable doors require a weather bar fitting to both leaves.
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 weather seal fitted between the 2 leaves. 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.  Remember, any cut outs of the door will need to be fully decorated to prevent water ingress.
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.
 When storing a door prior to installation, do not lean or stand the door as it will encourage the door to twist or bow.  Always store the door laying level and flat resting on support timbers.

Suitability of External Hardwood and Oak Doors

 All external hardwood and oak doors including our M & T and Dowelled ranges are veneered onto a solid core. They are therefore not suitable for use in locations subject to becoming wet or in very sunny conditions. We are unable to offer any warranty for these doors unless they are fully protected by a substantial porch or canopy. We do offer a comprehensive range of GRP, Composite and Bespoke Timber Doorsets that are more suited to these conditions. If you are in any doubt, please call us to discuss this topic with one of our door specialists.

Finishing Guidelines for External Doors

Oak external doors are not suitable for painting and should only be stained. For these doors we highly recommend using Sikkens Cetol HLS Plus for the base 2 coats and Sikkens Cetol Filter 7 Plus for the top 2 coats. (totalling a minimum of 4 coats).
All timber surfaces of external doors must be given a total of four coats of high performance wood-stain or paint. It is important to apply the treatment to the door before final installation and touch up with four coats any areas of the door that have been affected by installation. Bare timber doors will require a light sanding prior to finishing.
When applying the finish pay particular attention to sealing the timber 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 any visible end grain at 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 fished 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.
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.
Clear translucent coatings are not recommended as the timber may discolour through UV degradation.
To ensure the long life and appearance of the door, all coatings should be wiped down annually to remove any surface pollution. Periodically check the finishing treatment and touch up as necessary. Fully retreat the door as required and depending on degree of exposure to the weather.
 The aim is to keep any water from penetrating your door.  If you notice areas that need attention, please treat them straight away.
 We recommend for doors facing a westerly or southerly direction that a very light colour of finish is applied.  Dark colours absorb much more heat from the sun and will cause a faster breakdown of the painted surface and therefore require much more maintenance.  Timber is a natural product so performs slightly differently throughout the year, seasonal adjustment may be required to ensure ongoing performance.

Do’s
 Use a ‘High Build’ tinted wood-stain or good quality exterior paint. We prefer to use’ Sikkens Rubbol Satura Plus’ base and top coat paints or ‘Sikkens Cetol HLS Plus and Filter 7 Plus’ if staining.

• Apply a minimum of 4 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.

 Don’ts

• Do not use thin penetrating seals, oils, wax, dyes, preservatives or hard, brittle varnish finishes
• Do not use waxes, polishes, dyes oils including Danish oil, yacht varnish or lacquers as these do not protect the hardwood or oak standard external doors.
• Do not use water based or quick drying products
• Do not apply stains or paints in damp / wet weather
• Do not use thinned / mixed types paints or stains
• Do not mix incompatible products, e.g. paint on one door face and stain on the opposite face.

Maintenance of External Door

To ensure the long life and appearance of the doors and frame, all coatings should be wiped down annually to remove any surface pollution and check the finishing treatment and touch up as necessary. Fully retreat the door every few years or as required and depending on degree of exposure. Doors located in exposed areas will require more frequent maintenance coats. Wood stain and Paint finishes are not interchangeable: Using a white paint on an Oak stain finished product and vice versa will not work.

The finish coat should be wiped down with clean water to remove dust, insects and other contaminants, as these can form a base for algae and fungi growth. The coating surface should be inspected for mechanical damage and affected areas repaired accordingly.
NB: Storing, installing or finishing the product in a manner not detailed in the instructions may invalidate the warranty.  Please refer to our Terms and Conditions for installing hardwood and oak external doors.

Installation Guidelines for Internal Doors

 When trimming a door to fit, between 4mm and 6mm can be removed from each edge of a door to height and width. The amount depends on the factory of origin.  Please check with us to confirm.  Taking more than the maximum from the edge of a door can weaken or damage the door and will go against the guarantee. Any reduction must be removed evenly from each edge of the door, e.g. to trim your door by 6mm in width, remove 3mm off each side. NB: This excludes Fire Doors, Bi-Folds and rebated pairs.
Three hinges should be used to hang doors, particularly on glazed, heavyweight and fire doors or where large differences in temperature or humidity may occur, such as bathrooms.
Locks and latches should not be fitted adjacent to door mid-rails where the joint may be compromised.
All hardware screw holes should be pre-drilled to prevent splitting of the timber.  Paint ‘N’ Peel (glass protection film) should not be removed until painting or staining has been completed.  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.
Fire doors have individual fitting guidelines and the installer must refer to the Global Assessment Report referenced on the front of the fire door label.
Bi-fold doors are supplied with a track and folding hardware and should not be trimmed.  Rebated Door Pairs are supplied with separate instructions for fitting / trimming.

Finishing Guidelines for Internal Doors

• Use a good quality oil-based paint or varnish. We prefer to use Dulux satin wood or gloss oil-based paints and Sikkens TLS stain varnishes.
• Apply to all faces and edges
• Apply the same number of coats equally to each side of the door and the face, edges, lock, latch and hinge cut-outs
• Apply at least 1 coat of finish as soon as possible after unpacking the door
• Check that the finish manufacturers’ product is suitable for veneered / engineered doors.

• Do not use thin penetrating seals, oils, wax, dyes or hard, brittle finishes
• Do not use thinned / mixed paints or stains
• Do not mix incompatible products, e.g. paint on one door face and stain on the other face

Maintenance of Internal Doors