Technical Info

Door Construction

TDM’s timber doors are manufactured using our Tech form technology for added strength and durability.

Tech form combines the natural properties of timber with technology to produce a door that looks and feels like solid timber without sacrificing on performance.

By using Tech form, we ensure that our doors have a stile that remains true and will not warp, shrink, crack or twist under pressure. Tech form doors have a solid internal core of laminated timber lengths, giving a uniform stile and cross-rail construction for maximum strength and durability.

The exposed surface is then covered with premium grade veneer to give it that solid wood appearance.


The BB door has been developed at TDM for many years and performs better than any other timber door that we manufacture.

Our BB stable doors are completely revisable and can be hung on any side. The durable construction methods used by TDM ensures that the doors are warp and twist resistant.

Our BB doors can withstand any weather conditions and are the only true Class 1 exterior SABS approved doors in South Africa.

The boiler at TDM was designed to improve efficiency in various ways throughout the manufacturing process. Heat and steam is generated for the drying of timber and for powering certain machinery while also helping to produce its own fuel.

Wood laminating presses which produce shelving and TDM’s Tech form composite product are also powered by the boiler which releases no harmful emissions into the atmosphere.
Our boiler is so environmentally conscious, even though up to 800 kilograms of wood is fed into it every hour, only a wheelbarrow of ash remains at the end of the day. Even the water that the boiler uses to produce steam is piped back after it condenses to be re-used.

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TECHFORM® – Using technology to solve nature’s problems.

Wood is a pretty amazing natural product that has unique properties. Not only is it aesthetically pleasing, it is a strong, hard, tough and dense material that is well suited to the manufacture of many things we take for granted in our everyday lives. Although easily worked, wood is very durable and in the right conditions it can last for hundreds, or even thousands of years.

But it does have some weak points. Its physical properties are not distributed uniformly throughout its length. As a result, wood can warp, twist, shrink and crack, all things that are not desirable in the manufacture of doors or shelving.

TDM has developed a way to engineer wood that overcomes these shortcomings. By combining the great natural properties of wood with the best technology available, TDM has managed to create a product that actually improves on nature’s design. They call it Tech form®.

By gluing or laminating narrower planks of solid wood together, with the wood grain joined in alternating directions, some of the natural movement inherent in wood can be eliminated. The process results in a length of wood that will not succumb to any of the weaknesses of a solid piece of wood, and once the laminated Tech form® timber is covered with premium veneer, one has the best of both worlds – an apparently solid length of wood with none of the weaknesses.
Tech form® doors are engineered using a solid internal core of laminated timber lengths that have a uniform stile and cross-rail construction, ensuring maximum strength and stability.

Tech form®  doors can be produced with consistent colour matching and can be counted on to deliver superior performance.

Treatment and Maintenance

Exterior and Interior Doors


  • Proper treatment of wooden doors is essential in our harsh South African climate.
  • TDM Doors should be sealed on all 6 sides with a quality wood sealer immediately after delivery and prior to installation.
  • Ideally 2 coats of sealer should be applier prior to installation and a final coat after fitment.
  • If doors are to be painted, a universal sealer should be applied as above to the 6 sides prior to painting the doors.


  • Once the door had been delivered, it should be stored flat on a level surface in a dry, well-ventilated area.
  • Avoid storing in direct sunlight. Doors should be sufficiently protected from the elements to avoid spoilage.
  • Doors should be stacked on load bearers to spread the weight.
  • Always handle with care so as not to scratch or mark the surface or edge of the door.


  • Your doors can be fitted during or after building. Your builder will be able to advise you which is best for your requirements.
  • All surfaces i.e. foundations, concrete floors and plastered walls must be dry when fitting the doors.
  • Your doors should be fitted by a qualified carpenter.
  • Select a good sealant which will minimise swelling and shrinkage.
  • Select a matching exterior enamel to seal all edges ensuring breather holes are filled. Ensure breather holes remain closed after trimming. Fill with matching exterior filler or silicone of required.
  • A maximum of 5mm trim should be allowed on all sides.


  • TDM Doors require maintenance on a regular basis for protection against the elements and to prolong the life and beauty of the product.
  • Follow the sealant manufacturer’s recommendations to treat your TDM doors at regular intervals.

How to Hang a Door


We guarantee our doors to be made of high grade materials and of excellent craftsmanship and suited to normal conditions i.e. not excessive heat, humidity, dryness or direct sunshine.  Timber is a natural product subject to changes due to variations of humidity and temperature, and whilst we take great care to ensure that the timber used has been treated to make it suitable for the place it will occupy, it is obvious that we cannot know the conditions of every situation in which our products are installed.

All TDM Doors are covered by a 1 year Guarantee in conjunction with our general sales conditions, commencing from date of delivery.  Any door found to have a Factory fault will be replaced free of charge.

Subject to the above, we shall not be held responsible for any incidental work or expenses arising out of, or because of, any defect in our products, and our liability shall in no case exceed our invoiced price.

All guarantees are conditional upon doors being treated in accordance with TDM recommendations for the handling and treatment of doors.

We are a Proudly South African Company!

Global Footprint

Glossary of Terms


Concealed edge (flush doors with one stile concealed with hardwood lip).


Concealed edges (flush doors with both stiles concealed with hardwood lips).

Beaded Cut Outs

Opening provided to flush doors with glazing beads for site glazing.


Timber members fitted diagonally between the rails and stiles of a framed door (usually after hanging). Braces must be fitted to rise from the hanging stile outwards to counteract the door raking (sagging).


The process of sanding the surfaces of a flush door blank to give it perfectly true and even faces before over veneering.


The internal structure of a flush door.

Cross Banding

(Flush doors) the structural skin of the flush door, consisting either of hardboard or 3mm thick hardwood veneer.


Exposed edges

Exterior Door

Door designed to cope with normal exterior atmosphere. Note that exterior doors are not designed to cope with continuous direct sunlight or driving rain. Please contact your TDM representative for the most suitable exterior door for your project.

Face Veneer

The decorative veneer of a flush door covering the cross banding.

FL & B

Framed ledged and batten door.


Framed, ledged, battened and braced door.

Flush Back

(Framed doors) term used when both batten and middle rail and bottom rail are concealed by a ply wood covering fitting flush with the top rail and stiles of a framed door.

H&C Rail

(Flush doors) extra rail provided to give solid fixing point for hat and coat hook.


Hollow core door.

Hinge Block

(Flush doors) extra timber added to give strength and to spread stresses at the hinge position.

HW Stiles

Hardwood stiles (flush doors with exposed stiles made from hardwood).

Interior Door

Door designed for interior use only.

Lock Block

(Flush doors) additional timber provided to add strength round the lock position and solid fixing points for lock furniture.


Open Back framed doors term used to indicate that the battens of a framed door are exposed on the inside.

Plain Cut Outs

Opening provided to flush doors to accept ventilation grilles.

Ply Back

Framed doors term used when ply wood covering is fixed hard against the inside of the battens of a framed door (all rails left exposed).

Post Lipped

Flush doors with hardwood edges applied after Veneering.


Flush doors with hardwood edges applied after veneering. Semi solid and solid laminated doors.


Rebated meeting stiles normally used on all types of doors when paired.

Rounded Stiles

Used on all types of doors when hung on floor springs to swing. Both hanging and meeting stiles may be rounded or the hanging stiles may be rounded and the meeting stiles square on the same door.


Semi Exterior quality Solid Laminated door.


Interior Solid Laminated door.


Semi solid door.


Veneer over edges. Flush doors when the face veneer is applied to the edges of a pre-lipped calibrated door blank.

Weather Bar

Molded timber section fitted to the bottom of exterior doors to prevent water running under the bottom of door.