Doors

Door Types

Understanding doors is vital in choosing the right door for the right application. A certain door type may be more suitable to a specific application. As a customer, it is important that you have a basic understanding of the various door types so that you are able to choose the right door for your need based on facts and logic and not on intuition. In this article, we will be providing an insight into the various types of wooden doors based on their composition and structural integrity.

This article focuses on the various doors that are easily available in the market and effort has been taken to categorize them in a graphical way.  Each door will be discussed in detail in the coming articles. It is hoped that customers will be able to have a brief understanding of the different doors so that they are aware of the pros and cons of each door, their unique feature and will be in a better situation to gauge for themselves the perfect door for their requirements instead of relying on intuition or middlemen.

Solid doors can be further classified based on how the door is made.

  1. Solid timber panels
  2. Finger-jointed panels

Solid timber panels have been the traditional way of making solid doors. Wood timber is cut into panels of required dimensions and joined using conventional joints like mortise and tenon. Finger jointed panels are a relatively new method in solid doors. It makes use of smaller timber parts glued end to end to create longer panels Finger jointed panels make it possible to cover wider span and width than what is possible by solid timber panels. Concerns regarding glue strength and structural integrity of the panel compared to solid wood panel are offset by advantages like longer span, ability to send precut timber of exact lengths as specified by the client and the prospect of improving timber by eliminating defects and joining the pieces together.

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Solid Core Doors

Solid core doors are a class of wooden doors that are completely filled with wood or wood composite materials. Solid core doors make use of an engineered wood core which completely fills the wooden frame. The door is then provided with a veneer on both sides of the core.  The solid wood frame along with solid wood composite core provides high structural integrity and robustness. There will be many variants within solid core doors based on the solid core used, veneer used etc. We will see a few important ones.

  • Blockboard:

Though similarity exists in the manufacturing of plywood and blockwood, they should not be confused with one another. Blockboard consists of a solid core made from softwood strips placed edge to edge and sandwiched between hardwood veneers which are perpendicularly oriented. They are all interlocked together using glue under the effect of high pressure. Blockboard is one of the best alternative to plywood on account of its higher bending strength, reduced cost and manufacturing time which is a direct consequence of the presence of less number of thick sturdy veneers. The figure shown below gives an idea of the blockboard structure.

                                              Image Courtesy: Mendes et.al, Editoria UFLA, 1992

 

  • Particleboard

Particleboard is a composite panel made of cellulosic particles which act as the reinforcement phase and an adhesive or synthetic resin which acts as the matrix phase. The commonly used reinforcement is wood chips, sawdust though other materials like rice husk, agro wastes etc. are also used based on availability. They are bound together by a synthetic adhesive under appropriate conditions of heat and pressure. The particles are distinctive from fibers. It is an economical alternative to solid wood panels and has materialized as a nifty substitute for wood in many non-structural applications. Particleboard is cheaper, denser and more uniform than conventional wood and plywood and is substituted for them when appearance and strength are less important than cost. The shortcoming of unattractive surface finish can be remedied by painting the particleboard or by use of wood veneers that are glued onto the faces of the board. Waferboard and Strandboard are particleboards made from larger sized particles.

 Fibreboard

Fiberboards are a composite are made up of elements having same order of size as those of the wood cells, glued together by synthetic resin at high temperature and pressure. The term fiber can be roughly used to denote any element of the above mentioned shape and size, regardless of its origin. However, strictly speaking, fiber refers to a particular cell type in hardwood. As it must be obvious by now, the difference between particleboard and fiberboard lies in the size of the particles with the former made of larger particles.

Fibers can be classified on the basis of the density of the board.

  • Medium density fiberboard (MDF) : They have a density of about10-31lb/ft3
  • High density fiberboard (HDF): Also known as hardboard, they have a density of about 55-70lb/ft3

Fiberboards have advantages like smoother surface, ease of machinability, low cost and easily available raw materials.

 

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advantages such as smoother surface, easier machinability, and is an ideal panel material

as substrate for thin overlays used in indoor conditions [3]. MDF can be produced from

variety of natural fibers; but wood, because of its relative abundance and year-round

availability, is still the most important raw material. However, increasing demand of

forest resources for different uses has led to the shortage of wood supply. Therefore,

there is a need to find alternative raw materials or complete use of wood resources includ-

ing harvesting residues, annual plants, lumber and furniture plant residues, residues of

pulp plants, and recycled paper, etc

advantages such as smoother surface, easier machinability, and is an ideal panel material

as substrate for thin overlays used in indoor conditions [3]. MDF can be produced from

variety of natural fibers; but wood, because of its relative abundance and year-round

availability, is still the most important raw material. However, increasing demand of

forest resources for different uses has led to the shortage of wood supply. Therefore,

there is a need to find alternative raw materials or complete use of wood resources includ-

ing harvesting residues, annual plants, lumber and furniture plant residues, residues of

pulp plants, and recycled paper, etc

advantages such as smoother surface, easier machinability, and is an ideal panel material

as substrate for thin overlays used in indoor conditions [3]. MDF can be produced from

variety of natural fibers; but wood, because of its relative abundance and year-round

availability, is still the most important raw material. However, increasing demand of

forest resources for different uses has led to the shortage of wood supply. Therefore,

there is a need to find alternative raw materials or complete use of wood resources includ-

ing harvesting residues, annual plants, lumber and furniture plant residues, residues of

pulp plants, and recycled paper, etc

advantages such as smoother surface, easier machinability, and is an ideal panel material

as substrate for thin overlays used in indoor conditions [3]. MDF can be produced from

variety of natural fibers; but wood, because of its relative abundance and year-round

availability, is still the most important raw material. However, increasing demand of

forest resources for different uses has led to the shortage of wood supply. Therefore,

there is a need to find alternative raw materials or complete use of wood resources includ-

ing harvesting residues, annual plants, lumber and furniture plant residues, residues of

pulp plants, and recycled paper, etc

advantages such as smoother surface, easier machinability, and is an ideal panel material

as substrate for thin overlays used in indoor conditions [3]. MDF can be produced from

variety of natural fibers; but wood, because of its relative abundance and year-round

availability, is still the most important raw material. However, increasing demand of

forest resources for different uses has led to the shortage of wood supply. Therefore,

there is a need to find alternative raw materials or complete use of wood resources includ-

ing harvesting residues, annual plants, lumber and furniture plant residues, residues of

pulp plants, and recycled paper, etc

Hollow Core Doors

Hollow core doors refer to a solid wood framed door with a core of structural paper in a honeycomb pattern. The honeycomb is sandwiched between two door skins and is glued to hold the wood frame, honeycomb and the door skins together. The honeycomb forms the crux of door strength and structural rigidity. The honeycomb provides excellent moment of resistance that directly translates into high out of the plane strength and stiffness. Due to absence of any solid material within the core, these doors are extremely lightweight and an economic alternative to other conventional doors. The door skins are usually wrapped with a veneer to offer a high visual appeal. However, it should be noted that hollow doors are more suitable for interior purposes due to safety reasons.

Structurally stable frame ensures safe load distribution throughout the door and prevents any local failure.  These doors have the least cost, extremely lightweight and good strength to weight ratio. They are more feasible for interior spaces.

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