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Building System Design: Building Materials and Assembly

Wood

• There are four key topics related to wood, including classifications, defects, lumber, and composites.

Classification of Wood

• Softwoods come from conifers (evergreens) and have needles instead of leaves.
• Softwoods grow faster than hardwoods and do not shed leaves.
• Softwoods are used for feature walls, ceilings, furniture, doors, and windows and tend to be cheaper than hardwoods.
• Examples of softwoods include cedar, Douglas fir, pine, coconut, and hemlock.
• Hardwoods come from broad-leaves or deciduous leaves, grow slowly, and have denser wood.
• Hardwoods shed leaves annually and tend to be more expensive.
• Most Philippine timber comprises hardwood.
• Hardwoods are frequently used for flooring, cladding, paneling, fencing, boats, and outdoor decks.
• Examples of hardwoods include mahogany, narra, yakal, and acacia.

Wood Defects

• Bow defects involve a curve on the face of a board, typically extending from one end to the other.
• Crook defects involve a warp that happens along the edge of a board.
• Cup defects occur when the face of a board is hollow.
• Twist defects occur when there are multiple different bends in a board.
• Check defects involve a crack that occurs along the wood's growth rings.
• Check defects do not extend through the entire thickness of the board.
• With check defects, the corners of the board do not touch the ground when the board is flat on a surface.
• Knot defects are circular imperfections caused by a broken-off tree branch and are natural.
• Tight knots do not cause a significant problem, but dead or loose knots may fall out or leave a hole.
• Shake defects occur when the grain between the wood's growth rings separates.
• Shake defects can occur on the face of a board or below the surface.
• Split defects involve a crack in a piece of wood that goes all the way through the board.
• Wane defects occur when there is missing wood or an untrimmed edge along the side or corner of a board.
• Decay defects are caused by the attack of fungi.
• Pitch pocket defects involve well-defined openings between growth rings containing solid or liquid pitch.

Classification of Lumber

• There are four classifications of lumber: strips, board lumber, dimension lumber, and timbers.
• Strips are lumber less than 2" thick and less than 8" wide.
• Board lumber comprises pieces less than 2" thick and at least 8" wide.
• Dimension lumber includes pieces more than 2" and less than 5" in any dimension.
• Timbers comprise pieces 5" or more on the smallest dimension.

Deterioration of Lumber

• Molds, stains, and decay in wood are caused by fungi, and their growth depends on mild temperatures and dampness.
• Most decay occurs in wood with a moisture content above the fiber saturation point.
• Wood maintained at 20% M.C. or less is generally safe from fungus damage.
• Three types of insects lead to the deterioration of lumber: subterranean termites, drywood termites, and carpenter ants/powderpost beetles.
• Drywood termites infest dry, sound wood, structural lumber, dead limbs on trees, utility poles, decks, fences, lumber in storage, and furniture.
• Drywood termites don't require contact with soil, unlike subterranean termites.
• The feeding patterns of drywood termites cut across the grain of wood, leaving chambers and tunnels filled with fecal pellets.
• Fecal pellets, with their distinctive appearance and six longitudinal flattened sides, may indicate their presence.
• Carpenter ants excavate wood and form smooth tunnels inside to create nests, but do not eat the wood.
• The external sign of a carpenter ant infestation is small openings on the surface of the wood and expelled debris.
• The debris expelled consists of sawdust-like shavings or fragments of insulation or insect body parts.
• Powderpost beetles are reddish-brown to black, with cylinder-shaped bodies ranging from 1/8 to 3/4 inches in length.
• Powderpost beetles have distinctly visible heads and antennae with two-jointed clubs.
• Deciduous trees are the primary food source for powderpost beetles, which they bore into.

Wood Composites

• Wood composites include a range of different derivative wood products.
• They are created by binding the strands, fibers, or boards of wood together.
• Wood composites are also known as manmade wood, engineered wood, and wood-plastic composite (WPC).
• Typically, wood composites are created from the same hardwoods and softwoods used for lumber.
• Wood scraps and waste create wood composites by mixing ground wood particles with heated thermoplastic resin.
• Most wood composites are produced in large sheets, typically 1220mm (4') x 2440mm (8').

Plywood

• Coatings or layers of protective material over the surface (veneers) are good only for interior use.
• Advantages of plywood include the approximate equalization of strength properties along its length and width.
• Plywood offers greater resistance to checking and splitting and less change in dimension due to moisture content.
• Types of Plywood include Ordinary, Form (high-density overlay of phenolic resin), Marine (waterproofed), and Fancy.
• Fancy plywood includes narra book match, kalantas rotary cut, tanguile ribbon grain, lauan rotary cut, dao book match, rosewood, and tanguile
• Standard plywood sizes: 3' x 6' (900mm x 1800mm) and 4' x 8' (1220mm x 2440mm).
• Standard plywood thickness: 3/16" (4.5mm) for double wall partitions and ceilings, 1/4" (6.0mm) for double wall partitions.
• Standard plywood thickness: 3/8" (10.0mm), 1/2" (12.0mm) for drawers and shelves, and 3/4" (19.0mm) for drawers/shelves/cabinet/closet doors.
• Standard plywood thickness: 1" (25.0mm) for cabinet/closet doors and sub-floors.

Hardboard

• Hardboard is made from small wood fibers and wood pulp pressed until densely impacted before being baked for added stability.
• Hardboard is cheaper compared to plywood where strength lacks importance.
• Hardboard has a smooth surface on one side and a screened surface on the other and is known as Masonite.
• There are three types of hardboard: standard, panel, and tempered.
• Standard hardboard is light brown in color, has a smooth surface on one side and a screened impression on the other.
• Standard hardboard is flexible, easy to bend, and suitable for interior use where moisture is not a concern.
• Panel hardboard is denser than standard but not as dense as tempered options.
• Tempered hardboard is the densest, made by impregnating standard board with tempering compound of oils and resins.
• Tempered hardboard is baked to polymerize the tempering materials.
• It is dark brown in color, brittle and stiff, with improved machining qualities, resistance to moisture and penetration, and ideal for exterior use.
• Hardboard panel sizes are usually 4'x8' (1220mm x 2440mm) with thicknesses of 1/8" (3mm), 3/16" (4.5mm) or 1/4" (6mm).
• It is obtainable either with a plain, textured, or perforated surface.
• Hardboard brand names include LAWANIT and LAWANEX standard and tempered boards, as well as MASONITE boards.

Chipboard

• Chipboard (particle board/low-density fiber board) is made by bonding wood particles with an adhesive under heat and pressure.
• This creates a rigid board with a smooth surface, often faced with veneer.
• Chipboard is available in normal, medium, and high densities by binding phenolic resin or urea formaldehyde glue.
• Normal density chipboard is fairly soft and "flaky".
• High-density chipboard is very solid and hard and used for worktops and fire doors.
• Medium density chipboard falls somewhere in between normal and high.
• Chipboard advantages include cost-effectiveness and versatility of uses.
• The disadvantage of chipboard is its porous texture, which makes it water absorbent and prone to swelling.
• Chipboard can be used on kitchen worktops/cabinets, for building insulation, trims/mouldings, and sound deadening/absorption
• Melamine-faced chipboard (MFC) marks a key variation.

MDF Board

• MDF Board, an engineered wood product, comes from breaking down softwood into wood fibers in a defibrator, which are combined with wax.
• The mixture is held together with a resin binder, forming panels by applying high temperature and pressure.
• MDF is made up of separated fibers (not wood veneers), but can be used similarly to plywood.
• MDF is much more dense than normal particle board.
• MDF offers very smooth surfaces, low tear out when sawn, attractive finished surfaces when painted, and mild reaction to moisture.
• MDF is often covered in melamine or a veneer, which can form a prelaminated board.
• MDF panel sizes are generally 4'x8' (1220mm x 2440mm) and 3/16" (4.5mm) or 1/4" (6mm), 1/2" (12mm) and 3/4" (19 mm) in thickness.

Gypsum Board

• Gypsum board is a non-combustible building board with a gypsum core enclosed in tough, smooth paper.
• Gypsum board is designed to be used without the addition of plaster for walls, ceilings, or partitions.
• It is extensively used in "dry-wall" construction, where plaster is eliminated.
• Brand Names include BORAL and ELEPHANT.
• Square Edges are for cover-strip jointing, visible butt-jointed paneling, clamp fixing, and free suspension.
• Tapered Edges are for smooth seamless jointing and jointless wall and ceiling paneling.

Fiber Cement Board

• Fiber cement board is also called ficem board or fiber reinforced (FRC).
• Fiber cement board is comprised of 72% Portland Cement, 20% mineralized cellulose fibers, and 8% calcium carbonate.
• It possesses durable, fire-resistant, is insect-resistant, and offers a great appearance.
• Fiber cement board has disadvantages that it is heavy, brittle, dusty, and has a higher cost.
• Available thickness: 3.5mm, 4.5mm, 6mm, 9mm, 12mm, 18mm
• Brands include James Hardie, Shera, Gardner, and SCG.

Masonry

• Masonry marks a construction technique or trade that involves the use of individual units like bricks, stones or concrete.
• These blocks are bonded together with mortar to create a structurally sound structure.
• Masonry involves the careful arrangement and placement of units, typically rectangular, to form structural elements.
• Masonry is utilized in walls, arches, columns and other components.
• Types of masonry include bricks, stones, concrete blocks, glass blocks, and composite masonry blocks.

Sealant and Waterproof

• Sealants mark materials to fill gaps, seams, and joints to prevent air, water, dust, or other substances from passing through.
• Sealants are typically flexible and can accommodate movement or expansion within a building
• Sealants are categorized into types based on their chemical composition, such as silicone, acrylic, polyurethane, and epoxy sealants.
• Silicone sealants are widely used for excellent weather/temperature resistance, flexibility, and durability.
• Silicone sealants are commonly applied for sealing joints in windows, doors, and curtain walls.
• Acrylic sealants are water-based and offer good adhesion to various substrates
• Acrylic sealants are often used for interior applications, such as filling cracks and gaps in drywall or baseboards.
• Polyurethane sealants give excellent adhesion, flexibility, and resistance to weathering and high-stress areas/chemicals.
• Polyurethane adhesives are commonly used in construction and expansion joints.
• Epoxy Sealants showcase exceptional strength, durability, and chemical resistance.
• Epoxy sealants are suitable for bonding and sealing applications requiring high performance, like structural/anchoring.
• Waterproofing describes the process of making a structure or surface resistant to water penetration.
• This involves applying specific materials or systems to prevent water damage from entering the building envelope.
• Waterproofing implemented in vulnerable areas that susceptible to water infiltration.
• Waterproofing creates a barrier that prevents water from seeping through the structure and causing damage.

Waterproofing Methods

• Liquid membranes or coatings are applied directly onto the surface to form a seamless or protective layer.
• These are sprayed, rolled, or brushed onto surfaces and can provide excellent waterproofing properties.
• Cementitious waterproofing involves the application of cement-based coatings or slurries that bond to the surface.
• This forms a rigid waterproof layer commonly used for below-grade structures and concrete surfaces.
• Sheet membranes comprise pre-manufactured materials like bitumen, PVC, or modified asphalt.
• They are typically applied in multiple layers and adhered to the substrate using adhesives or heat-welding techniques.
• Bentonite clay is used to create a self-sealing membrane that swells upon contact with water.
• It is often used in below grade applications combined with other waterproofing systems.
• Polyurethane membranes or coatings offer excellent flexibility, durability, and resistance to water.
• They can be applied as liquid coatings to cure into a seamless, elastomeric layer.
• Integral waterproofing additives are admixtures added to concrete/mortar mixes to enhance their resistance to water penetration.
• They work by reducing capillary porosity and improving the overall durability of the structure.

Hardware and Mechanisms

• Hardware is used in construction, such as bolts, nails, screws, and fittings(catches, hinges, locks, etc.) and tools, classified into rough and finish.
• Rough hardware marks hardware meant to be concealed, such as bolts, nails, screws/spikes, and other metal fittings.
• Finish, also called architectural hardware, has a finished appearance (hinges, locks, catches, etc.).
• Finish hardware is typically used with doors, windows, and cabinets and considered part of the decorative treatment.

Types of Rough Hardware

• Common Wire Nails are a cut or wire low-carbon steel nail with a slender plain shank and medium diamond point.
• They are used where finish is unimportant (i.e. framing).
• Finishing nails, constructed of finer wire versus the common nail, have a brad-type head.
• Given this quality, it can be set below the surface and covered putty.
• Brad nails mark a small finishing nail of the same thickness, with an almost flush head.
• Box nails are thinner than common nails; they possess a smooth or barbed long shank.
• Casing nails have a slender body with a small, slightly flared head, that is generally used for finishing work.
• Masonry nails are hardened steel with a knurled or fluted shank (esp. used for fastening to masonry).
• Ring-shank nails have a series of ring-like grooves around the shank to increase its holding power.
• Clinch nails are designed for clinching.
• Clinching is securing a nail, staple, screw, or bolt by hammering the protruding point so that it is bent over.
• Roofing nails are short with a barbed/ring shank and a large head.
• Roofing nails may be bright or galvanized and often provided with a neoprene, lead, or plastic washer.
• Metal Lath Nails are specially designed to secure metal lath.
• Electrician's Staple Nails are U-shaped piece of metal/heavy wire is fixed to wood panel and driven into a surface to secure.
• Concrete nails are hardened steel having a flat countersunk head and a diamond point and used for nailing concrete or mansonry.
• Face-nailing involves nailing in which the nails are driven perpendicular to the face of the material.
• Blind-nailing (concealed/secret) involves the absence of nail heads.
• Toe-nailing (Skew or Tusk Nailing) marks a process of nailing obliquely to the surfaces being joined.
• Screws are externally threaded fasteners.
• Wood screws are helically threaded metal fasteners with a pointed end.
• Wood screws form threads when driven into wood or other resilient material.
• Metal screws fasten by screwing into metal.
• Lag Screw, Lag Bolts are bolts having a square head with a thin, coarse-pitched thread.
• Nuts mark a short metal block having is threaded to receive a screw, bolt, etc.
• Machine bolts are a straight shank with (square, hexagonal, button, or countersunk) head.
• Carriage bolts are a circular head with a means of preventing rotation of the bolt.
• Toggle bolts have a spring nut where flanged wings close against a spring before the bolt goes to the hole.
• Expansion bolts (or expansion shields) have an anchoring device with an expandable socket, that swells as the bolt is tightened into it.

Types of Finish Hardware

• Door hardware is an example of finish hardware.

Functions of Door Hardware

• Hanging the Door achieved through hinges, pivots, and combination pivots.
• Operating involves handles, latches, push plates, and pull bars.
• Closing is completed through door closures, and combination pivots/closures.
• Locking requires locksets, dead bolts, flush bolts, electric locks, and other special devices.
• Sealing involves weather stripping, sound seals, and smoke seals. Protecting involves kick plates or corner protection.
• Hinges are moveable joints used with two plates joined together by a pin.
• Hinges attach, support, turn a door about a pivot, and connect it to its frame, enabling it to swing open or closed.
• Specialty hinges exist that are invisible, swing clear, possess an olive knuckle, and are fitted with a continuous gear.
• Specialty hinges are available with a button tip, steeple, oval, ball, or hospital tips.
• Butt hinges consist of two leaves and are also sometimes referred to as butts, since typically attached to door's butts.
• Knobs are more or less spherical handles, that in most cases, are used for operating and locking.
• Knobs can be matched with various plates of finish and function.
• A knob rose describes a disk or plate, round in its appearance, secured to door where the doorknob resides to serve as attachment.
• Escutcheons are protective around door keyhole.
• A strike, strike plate, or striking plate is either bored or counter sunk inside doorjamb.
• Lip strike is projection which the bolt of a lock strikes first, when door is shut as protection for surrounding door.
• Closers are devices that help doors return to its initial closing position after being left to open.
• Pivots provide another solution than hinges, for doors that may call for frameless styling.
• Panic Hardware meets a building code that is required in an event safety.
• Push plates and pull bars offer door operation for doors lacking automatic latching (also used on doors of commercial kitchens.).
• Door stops possess rubber bumpers and are metal-made to act as buffers for construction.
• Astragals serve best between doors with its vertical members to seal opening, act as door stop, or provide extra security when doors stay closed.
• Barrel bolts are manually operated sliding rods attached to doors for security.
• Chain Door-Fasteners create limit door openings to be the chain's given door, as opposed to freely opening.
• A chain bolt resides at door tops and has a spring bolt to it moved by means of chain.
• Foot bolts keep door closed as bottom of door remains fixed as spring holds up.
• Flush bolts work to inactive leaves of double doors by locking it via surface.
• Barrel bolt is moves into casing in cylindrical shape.