Microsoft Powerpoint - Wood Conservation

7/30/2019 Microsoft Powerpoint - Wood Conservation

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WOOD PRESERVATION

ARCH. SEPIDEH P. AHMADZADEH


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WOOD?

Wood The hard fibrous material that forms

the main substance of the trunk or branches

of a tree or shrub. Such material when cut is used as timber or

fuel


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WOOD CLASSIFICATION

HARDWOOD - any leaf bearing tree

Hardwood trees are angiosperms, plants that

produce seeds with some sort of covering.

This might be a fruit, such as an apple, or a

hard shell, such as an acorn.

OAK, MAPLE, MAHOGANY, CHERRY, WALNUT,

TEAK AND ROSEWOOD

SOFTWOOD - any cone bearing tree.

Softwoods, on the other hand, are

gymnosperms. These plants let seeds fall to the

ground as is, with no covering.

PINE, ASH, HICKORY, BEECH, BIRCH, CEDAR,

REDWOOD, HEMLOCK, FIR AND SPRUCE


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INDEGENOUS WOOD IN THE

PHILIPPINES Bamboo - for posts, flooring, sidings, roofing,

Molave Queen of Philippine Woods which was impervious to insects, and so

hard that it didnt even float in water. Used for:

principal posts, beams and other supports of building

Popular for furniture, organ cases, santos and panels for paintings

Yacal, Guijo, Ipil and Dungon slightly less hard, used also for similarimportant architectural functions.

Narra prized for its blood-sheen, along with banaba, guijo, mangachupoy

ideal for floorboards.


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WOOD USES:

FUEL

CONSTRUCTION

FURNITURE AND UTENSIL ARTS

SPORTS AND RECREATIONAL EQUIPMENT

MEDICINE


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PREPARATION OF WOOD

Air Drying

Outdoors


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KILN DRYING


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WOOD PRESERVATION

All measures that are taken to ensure a long life of wood fall under the definition woodpreservation (timber treatment).

A preservative is a natural or synthetic chemical that is added to wood, to preventdecomposition by microbial growth or by undesirable chemical changes.

TYPES OF WOOD PROTECTION:

Wood protection by construction design means:

keeping off the causes of harm by the appropriate structural arrangements and design

Wood protection by selection of materials:selection of more resistant or less sensitive materials (wood or glue type, etc., for example).

Artificial wood protection:

in the most general sense, treatment with chemical protective media, paints or varnishes,which are introduced into or onto the material.


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HISTORY

Treatment of wood has been practised at thebeginning of recorded history.

ancient Greece during Alexander the Greatsrule, where bridge wood was soaked in oliveoil.

The Romans also protected their wood bybrushing their ship hulls with tar.


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4000bc God tells noah to use tar in building the ark.

2000bc gilgamesh epic tar is poured over wood.

484-424bc aluminium potassium sulphate used as fire retardant.

23-79ad plinius secundus cedar oil resistant to insect & decay.

statue of diana in ephesus impregnated with nard oil.

Fourth century palladius preservation with salt water.

1445 franckensepiegel timber for a church is boiled in brine.

Breaf history


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1452-1419 leonardo da vinci paintings panel & carvings are coated with

mercury (ii)chloride, arsenic(iii)oxide.

1469-1524 vasco da gama ship building chared against ship worm.

1500 termites controlled with mercury (ii)chloride, arsenic(iii)oxide.

1718 hiarne awarded patent in sweden wood balm based on copper oriron sulphate. 1st commercially prepared wood preservative.

1756 use of plant tar & extractives as preservatives in england and america

1815 Thomas wade- zinc chloride as a preservative.

1832 kyan british patent for vat treatment with mercury chlorideaqueous sollution. Beginning of modern wood preservation.


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WOOD PROBLEMS


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BIO-DETERORIATION OF WOOD is the attack on man-made materials by living

organisms.

Molds and Fungus Stains

Molds and fungus stains are confined to a great extent

to sapwood and are of various colors. The principal

fungus stains are usually referred to as sap stain or

blue stain. The distinction between molding andstaining is made primarily on the basis of the depth of

discoloration.

Risk of Mold and Stain

Increase wood permeability

Reduce surface appearance

Reduce toughness

Health effects (spores / volatiles / contact)

Factors Affecting Fungal Growth

Sapwood Content

Temperature

Wood Moisture Content

Time of year

Treatments

MOLD PREVENTION

Short log storageKiln in within 48 hours

of sawing

Keep wood dry

Chemical treatment


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Mold Treatment and removal

Bleach

Borax

Vinegar

AmmoniaHydrogen peroxide

Detergent

Baking soda

Tea tree oil

Grapefruit seed extract

How to Kill Mold with Bleach

For killing mold with bleach use a ratio of one cup

of bleach per gallon of water (i.e. about 1 part

bleach to 10 parts water).

Apply the solution to non-porous surfaces with

mold growth either by using a spray bottle or by

using a bucket and a sponge or cloth.

You don't need to rinse the surface afterwards

(unless it is used for food preparation or a surfacewhich may be touched by small children or pets)

as the bleach will inhibit mold growing in the

future


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CHEMICAL STAIN

Chemical Stains Nonmicrobial or chemical stains are difficult to control and

represent substantial loss in wood quality. These stainsinclude a variety of discolorations in wood that are oftenpromoted by slow drying of lumber and warm to hottemperatures. Such conditions allow naturally occurringchemicals in wood to react with air (enzymatic oxidation) toform a new chemical that is typically dark in color.

How to Remove1. Paint a layer of the chemical stripper along the surface of the woodstain. Allow it to set in for 5 minutes, or according to themanufacturer's label.

2. Scrub the solvent with the brush to pull the stain from deep in thewood grain. Work with the grain of the wood to make sure thesolvent penetrates into the wood where stain adheres.

3. Wipe away any solvent and stain with a wet rag. Give the woodsome time to dry.

4. Apply a layer of two-part bleach to the wood to remove anylingering stain deep in the wood pores. Scrub the wood once againwith the brush. Let the bleach evaporate before sanding.

5. Sand the wood to create a smooth layer free from any stain. Use afine-grit paper to prepare the wood for a new stain or paint.


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DECAY

Decay

A wood-decay fungus is a variety offungus that digests

moist wood, causing it to rot. Some wood-decay fungi attack

dead wood, such as brown rot, and some, such

asArmillaria (Honey fungus), are parasitic and colonize living

trees. Fungi that not only grow on wood but actually cause it todecay, are called lignicolous fungi. Various lignicolous fungi

consume wood in various ways; for example, some attack

the carbohydrates in wood, and some others decay lignin.

Wood-decay fungi can be classified according to the type of

decay that they cause. The best-known types are

brown rot

soft rot

white rot brown rot

white rot


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Preventing wood decay Use Logs Immediately

In order to prevent decay in wood, use the logs without delay. After the logs are cut, the bark

should be removed right away too. In order to minimize the chances of fungi and insects

colonizing the logs, it is best that the trees and logs be cut in the late fall or winter.

Chemical Treatment

After the logs are cut and debarked, they should be dipped in a preservative chemical and

stored, preferably under a roof and off the ground to reduce the exposure to moisture fromdirect contact with the ground. The chemical treatment protects the logs while they dry.

Drying Logs

Following the debarking of the logs, they can be kiln-dried either completely or partially. The

temperature attained during this process kills the existing fungi in the logs. This helps prevent

the logs from getting wet or gathering moisture when stored later.

Fumigation Fumigating the logs with toxic gases is another alternative after the logs have been debarked.

This process is short-lived, however, and does not provide long-lasting protection from

insects and fungi.


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Preservative Treatment Before they are handled or stored, logs can be treated with specific preservatives. This

treatment includes a superficial dip in fungicides to control molds and stain fungi, diptreatment of unseasoned logs in diffusible chemicals to control insects and decay fungi, andpressure treatment of seasoned logs to control insects and decay fungi.

Designing Log Homes

Proper building design and construction techniques need to be used to protect logs fromexposure to excessive water and moisture. In order to keep the logs dry, wide roof overhangsand long porches are important, especially on the side of the structure, which is mostfrequently exposed to wind-blown rain. Preservative chemicals are also useful in protectinglog homes. Drainage needs to be properly designed so that any water that accumulatesfrom rain runs off of the house on all sides.

Using Paints A wood preservative containing a water-repellent should be applied to the exterior surface of

logs as soon as the house is erected. The preservative should contain both a fungicide and aninsecticide. The sides of the home exposed to frequent rain and moisture should bethoroughly treated. Periodic maintenance will ensure the logs' longevity.


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TERMITES

Any of numerous pale-colored, usually soft-bodied

social insects of the order Isoptera that live mostly in

warm regions and many species of which feed on

wood, often destroying trees and wooden structures.

Also called white ant.

(a) beneath buildings without basements that were

erected on a concrete slab foundation or were

built over a crawl space that is poorly drained and

ventilated

(b) in any substructure wood component close to the

ground or an earth fill

The principal method of protecting buildings in high

termite areas is to thoroughly treat the soil adjacent

to the foundation walls and piers beneath the building

with a soil insecticide.


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TERMITE PREVENTION

termites are attracted to wood, so remove potential termite food awayfrom buildings - their food can include timber stacks, old stumps, buildingrefuse, garden decoration such as sleepers and logs

waste timber from construction activities is often left in place or storedunder the house remove all timber formwork

timber can be treated to prevent termite attack, and some timbers arenaturally resistant - use treated or naturally resistant timber when it is incontact with, or close to, soil

termites are attracted to water, so fix leaking water pipes, drains, showers,sinks etc, plus capture water from air conditioning units

termites prefer humid conditions, so keep air under the house dry byimproving sub-floor ventilation, drainage and access

termites cannot chew through properly laid concrete, so ensure concreteslab is properly designed, compacted, and cured

termite colonies can sometimes be located - it is possible to eliminatecolonies by killing the reproductives (the queen and the king).


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A. Pre-construction Services

1. termite mound demolition2. termite soil treatment/ soil poisoning

3. treatment on flooring

4. treatment on hollow block

B. Post-Construction Services

1. slab injection

2. spot termite application

3. Baiting System (Sentricon)

Pest Management Program


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WEATHERING

Wood is prone to weathering from severaldifferent forces. Direct sunlight, exposure towater, freezing and thawing, and drying outcan all cause wood to appear weathered.Signs of weathering include fading to gray,warping, splitting and cracking.

Prevention:

Redwood and cedar have some naturalresistance to weathering, but all woods willsuccumb to damage from wind, sun andwater after time. If you like a natural look, letthe wood weather to the desired color. On asunny day, when the wood is dry, spray orbrush a clear sealer onto it. If a natural look is

not desired, paint with a good primer thatwill soak into the wood, let it dry and thenpaint the wood. Check the protective surfacefor wear at least once a year, and repeatevery two years, regardless of appearance.


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SCRATCHES

On Woods with Natural Finish

Use furniture cleanser-conditioner to clean and blend color ofscratched area with natural finish.

To disguise minor scratches, use broken pieces of nutmeats, such apecan, English or black walnut, Brazil, or butternut.

Rub diagonally along scratch until it darkens.

To Color Scratch, Apply:

Colors-in-oil (such as burnt umber) thinned with turpentine.

Or varnish stain, ready-mixed in wood colors. If too concentrated,add stain to clear varnish of same brand.

Or colored varnish. May be added to clear varnish of same brand. Setcontainer in pan of hot water before applying.

Or clear varnish tinted with colors-in-oil.

Or commercial scratch remover.

Umber is a natural brown clay pigment that

contains iron and manganese oxides.


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REPAIRING DAMAGES

DAMAGED FINISHES MAY BE REPAIRED

Often damaged finishes can be repaired without

refinishing piece. White rings or spots may be caused by

moisture, heat, or alcohol. Paper sometimes adheres toa surface. Scratches or cigarette bums scar finishes.

Holes, gouges, and cracks may occur through use or

aging.


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PAPER ADHERED TO SURFACE

You May Use:

Lightweight oil (such as mineral, paraffin, olive, orlemon)

warmed; and 3/0 steel wool pad.

To Apply: Pour enough warm oil on surface tosaturate paper. Let stand. Rub lightly with steelwool.

Apply more warm oil; rub. Wipe surface with oil,then with a dry cloth.


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WHITE SPOTS OR RINGS

You May Use:

pumice powder, or cigarette ashes.

Lightweight oil.

3/0 steel wool pad.To Apply: Dust pumice or ashes over spot or ring; dipsteel wool pad into oil; rub lightly with grain of wood.Apply lightly to entire surface to prevent spotting; wipesurface with soft cloth.

OR USE: Salt and lightweight oil. To Apply: Dip finger intooil, then salt; rub spot with mixture. If white spot is old orvery deep, much rubbing may be needed.


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SMALL CRACKS NEAR AN EDGE

Repairs can be made over existing finish or

during refinishing, after several coats of finish

have been applied and are thoroughly dry.

Fill Cracks with Wood-Forming Plastic:

Soften plastic with denatured alcohol

solvent, if needed.

Add colors-in-oil to blend color of plasticto finished wood.

(Mix color several shades darker than you

desire it dries

to much lighter color.)


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GOUGES, HOLES, BURNS

When wood finishes are gouged or burned,

repairs may be made on existing finish. Or,

during refinishing, burns, holes, and gouges

may be filled after several coats of new finish

have been applied and are dry.

Denatured alcohol is used as a solvent and as fuel for spirit burners and camping stoves.

Because of the diversity of industrial uses for denatured alcohol, hundreds of additives and

denaturing methods have been used. The main additive has traditionally been

10% methanol, giving rise to the term "methylated spirits". Other typical additives

include isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone,

and denatonium.[1]


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Remove Discoloration or Char

Scrape charred spot or darkened edges of holes with a knife blade or3/0 steel wool wrapped around an orange stick or pencil.

Brush out scrapings with an old toothbrush.

Sponge charred area with denatured alcohol to bleach.

Repeat process, if necessary.Fill and Finish Damaged Area

If damaged area is shallow, fill it with several coats of

colored sealer or varnish if stained. Or use a clear sealer or

varnish.

If hole is deep and no larger than thumbnail, fill it with

lacquer stick.

If hole goes clear through, use spackling compound or woodformingplastic underneath. Fill top with lacquer stick.


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Grease

To Remove Grease From Woods:

In a well-ventilated area or outdoors, scrub surface with a drycleaning solvent such as Renuzit, Laiglon, or Afta. Scrub with a brush,then with 3/0 steel wool. Allow to dry thoroughly. Repeat two or threetimes, allowing about a day for drying between treatments.

Or: Make a paste of fuller's earth and a dry cleaning solvent.

Apply to greasy surface. Leave paste on wood 24 hours.

Then brush off. Repeat paste treatment if necessary.

No cleaning solvents are available that effectively remove

grease spots without some hazard to the user some solvents

are flammable; others are toxic.

Fuller's earth is usually highly plastic, sedimentary clays or clay-like earthy material used to

decolorize, filter, and purify animal, mineral, and vegetable oils and greases.


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Water Damage

Water damage caused to your furniture as a

result of flood or weather is not always as bad

as it seems. Often the damage is quite

manageable, or at least subject to partial

repair.


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Documents

Microsoft Powerpoint - Wood Conservation