Defect Atlas — Timber

Timber recorded as visibly damp or registering high values where moisture meters are used as a guide.

Darkened tone, damp feel, condensation on adjacent surfaces, slow drying after rainfall.

Direct water ingress, condensation, defective rainwater goods and contact with damp masonry may contribute.

• location and extent
• associated visible water pathways
• any meter readings recorded for guidance
• comparison with adjacent sound timber

“Elevated moisture was recorded at the base of the post, with damp staining extending approximately 200 mm above the floor.”

Discolouration of timber consistent with past or present wetting.

Darker tide marks, irregular patches, sometimes with associated salt or surface deposits.

Historic or current water ingress, run-off from adjacent fabric or defective junctions may be associated.

• location and pattern of staining
• relationship to water pathways above
• whether staining appears active or historic
• any associated softening or decay

“Damp staining was observed on the underside of the beam, in a pattern consistent with run-off from the gutter junction above.”

Loss of timber integrity associated with possible fungal activity. The atlas records observation; species identification is not implied.

Softened, discoloured or crumbling timber; loss of structural feel under light probing; sometimes visible fruiting bodies or mycelium.

Sustained elevated moisture and limited ventilation may be associated with fungal activity.

• extent and depth of affected timber
• any visible fungal growth or fruiting bodies
• evidence of cuboidal or stringy breakdown
• associated moisture pathway

“Apparent fungal decay was recorded at the bearing end of the beam, with softening of approximately the lower 40 mm.”

Patterns of decay commonly associated with sustained wetting, recorded as observation rather than diagnosis.

Darkened, soft, often stringy timber; loss of section in zones of repeated wetting; sometimes localised to one face.

Sustained water contact, often at junctions, end-grain or trapped zones, may be associated.

• extent and location
• relationship to water source and drying pathways
• depth of softening where assessable
• comparison with adjacent dry timber

“Indicators consistent with wet rot were recorded at the cill ends, with softening confined to the rebate adjacent to the masonry.”

Patterns of decay associated with conditions that can support dry-rot fungi, recorded as observation rather than diagnosis.

Dry, light, often cuboidal-cracked timber; sometimes off-white or grey mycelium; occasional rust-coloured spore deposits; characteristic odour reported by some surveyors.

Sustained dampness combined with poor ventilation, particularly behind linings or in concealed voids, may support such activity.

• extent and location
• presence of mycelium, strands or spore dust
• evidence of cuboidal cracking pattern
• concealed adjacent zones likely to have similar conditions

“Indicators consistent with dry rot were recorded behind the panelling adjacent to the chimney breast, including cuboidal cracking and a fine surface growth.”

Loss of resistance under light probing without other diagnostic features being conclusive.

Timber gives way under gentle probing; surface may appear sound but feel spongy; sometimes localised to one face.

Sustained moisture, early-stage fungal activity or insect damage beneath the surface may contribute.

• depth of softening where assessable
• extent across the element
• associated visible features
• relationship to moisture or fixing locations

“Softening was recorded along the lower edge of the rail, with light probing penetrating approximately 8 mm in places.”

A characteristic pattern of cracking that divides the timber into roughly cubic blocks across and along the grain.

Block-like fracture pattern visible at the surface; dry, brittle timber between cracks.

Loss of cellulose associated with certain fungal activity can produce this pattern; recorded as observation only.

• extent and depth
• associated dryness or brittleness
• presence of mycelium or surface growth
• concealed adjacent zones likely to be affected

“Cuboidal cracking was observed across the lower section of the joist end, with the timber dry and brittle between fractures.”

Visible fungal material on the surface of timber or adjacent fabric.

Strand-like, sheet-like or cotton-wool-like growths; may be white, grey, brown or rust-coloured.

Sustained moisture, limited ventilation and a suitable food source may support fungal growth.

• extent, colour and form of growth
• any associated odour
• extent of underlying decay where visible
• adjacent concealed voids

“A sheet of pale mycelium-like growth was recorded behind the skirting, extending approximately 300 mm along the wall plate.”

Small, generally round holes produced by wood-boring insects emerging from infested timber.

Pinpoint to several-millimetre holes, scattered or concentrated; sometimes with fresh, pale interior surfaces.

Wood-boring insect activity, current or historic, can produce exit holes; species identification is not implied.

• approximate hole diameter
• density and distribution
• evidence of fresh, light-coloured interior surfaces
• associated frass or bore dust

“Insect exit holes of approximately 1.5 mm diameter were recorded across the inner face of the panel, with no fresh bore dust observed at the time of survey.”

Fine powder produced by wood-boring insects, found below or within infested timber.

Fine, pale or biscuit-coloured powder; sometimes accumulating on horizontal surfaces beneath.

Recent insect activity may produce visible bore dust; older deposits can also persist.

• location of dust
• whether dust appears fresh or compacted
• associated exit holes
• evidence of recent disturbance

“A small accumulation of pale bore dust was recorded on the offset below the lintel, beneath several exit holes of similar diameter.”

Observations that may suggest current rather than historic insect activity.

Fresh, pale frass; sharp-edged exit holes with light interior surfaces; sometimes audible activity reported by occupants.

Environmental conditions suitable for ongoing insect activity may be associated; specialist identification is required for confirmation.

• evidence of fresh frass
• appearance of recent exit holes
• concentrations of activity
• associated moisture or environmental conditions

“Indicators consistent with active insect activity were recorded on the joist end, including fresh-appearing frass and sharp-edged exit holes.”

Evidence of past insect attack without indicators of current activity at the time of survey.

Weathered, dust-filled exit holes; no fresh frass; sometimes coating present over holes; consistent superficial appearance.

Past infestation under former environmental conditions may leave persistent surface evidence.

• extent across the element
• depth of penetration where assessable
• any apparent recent activity
• structural significance of affected timber

“Historic insect damage was recorded across the rafter face, with weathered holes and no fresh frass observed.”

Reduction of effective timber section produced by extensive insect tunnelling.

Friable, lace-like internal structure visible at fractures or exposed ends; reduced strength under probing; collapse of surface layers under light pressure.

Sustained insect activity, possibly compounded by moisture, may produce significant section loss.

• extent and depth of affected timber
• location relative to load paths
• evidence of recent activity
• comparison with adjacent sound timber

“Loss of section from insect attack was recorded at the bearing end of the lintel, with the lower 25 mm appearing significantly weakened.”

General departure from the original flat or straight geometry of a timber element.

Visible distortion of plane or alignment; gaps at junctions previously close-fitting; rocking when handled.

Drying, moisture cycling, original grain orientation and applied loading may contribute to warping.

• type and direction of warp
• extent across the element
• associated movement at joints
• evidence of progression where comparable records exist

“Warping was recorded across the door, with the leading edge standing approximately 8 mm proud at the head.”

Curved deflection of a long timber element away from its original axis.

Visible curvature along the length; gap between the timber and a straight edge or adjacent fabric.

Long-term loading, moisture movement or original grain features may contribute.

• approximate extent of bow
• direction relative to load and grain
• associated movement at supports
• implications for adjacent fabric

“Bowing was recorded in the central rafter, with approximately 15 mm of deflection observed against a straight edge.”

Curvature across the width of a board, producing a dished or domed cross section.

Concave or convex surface across the board; visible gap at the edges or middle when placed flat.

Differential moisture between faces, original tangential cut or sustained one-sided wetting may contribute.

• direction of cup
• extent across the width
• evidence of one-sided wetting
• associated joint opening

“Cupping was recorded on the floorboards adjacent to the threshold, with approximately 4 mm of deflection across the width.”

Spiral distortion of a timber element about its long axis.

Visible twist along the length; corners of a previously square section out of plane.

Original grain spirality, drying and moisture cycling may contribute to twisting.

• extent and direction of twist
• associated movement at fixings or joints
• implications for adjacent fabric
• comparison with original geometry where recorded

“Twisting was recorded along the stile, with approximately 6 mm of out-of-plane movement at the lower corner.”

Vertical or rotational movement of a timber element associated with movement of its support.

Sloping floors, tilted door frames, gaps at junctions, associated cracking in adjacent finishes.

Movement of foundations, bearings or supporting masonry may contribute to settlement effects in timber.

• direction and extent of movement
• associated cracking in adjacent fabric
• evidence that movement is recent or historic
• any signs of distress at bearings

“Settlement movement was recorded at the threshold, with the door frame leaning approximately 10 mm out of plumb at the head.”

Downward or out-of-plane movement of a timber element under load.

Visible sag in beams or floor structures, sometimes accompanied by cracking in finishes below.

Long-term loading, possible loss of section, moisture cycling or original sizing may contribute.

• approximate deflection magnitude
• evidence of progression
• associated section loss or decay
• implications for adjacent fabric and loadings

“Deflection of approximately 20 mm was recorded mid-span on the timber beam over the kitchen area.”

Fine surface cracks following the grain that do not pass through the full section.

Shallow, longitudinal cracks; sometimes a network across exposed faces; minor width.

Drying, moisture cycling and exposure to direct sun or heat may contribute to checking.

• extent and orientation
• depth where assessable
• relationship to grain and exposure
• association with coating breakdown

“Checking was recorded across the south-facing face of the sash, with multiple shallow cracks following the grain.”

Cracks through timber that are open and may extend deeper than surface checking.

Clearly open cracks along the grain; sometimes admitting debris or moisture; visible depth.

Drying, fixings under stress, impact or sustained loading may contribute.

• length, width and depth where measurable
• orientation relative to grain and loading
• evidence of progression
• implications for water shedding

“An open split was recorded on the top rail, approximately 180 mm long and 2 mm wide, running with the grain.”

Separations within the timber, often along growth rings, that may have developed during growth, conversion or service.

Curved cracks following growth rings, sometimes only visible at end grain; can extend along the length.

Original growth stresses, drying and seasonal moisture movement may be associated.

• type of shake where identifiable
• extent visible at end grain and along the length
• implications for strength and water ingress
• association with fixings

“A ring shake was recorded at the end of the beam, visible across approximately one third of the cross section.”

Cracks running from fixing positions through a significant portion of the section.

Visible cracks initiating at nails, bolts or screws; sometimes accompanied by movement of the fixing.

Fixings inserted close to ends, oversized fixings, drying around fixings or stress at the joint may contribute.

• location and orientation of split
• fixing type and condition
• evidence of movement at the joint
• implications for structural performance

“Through-section splitting was recorded around the bolt at the heel of the truss, extending approximately 90 mm from the fixing.”

Visible separation between timber members or between timber and adjacent fabric at previously close-fitting joints.

Gaps at junctions, sometimes admitting debris, vegetation or water; visible movement under handling.

Drying shrinkage, settlement, fixing failure or original construction may contribute.

• location and approximate width
• evidence of movement
• presence of debris or moisture within the gap
• implications for water shedding and stability

“Open joints were recorded between the sash and the frame, with gaps of up to 4 mm visible at the meeting rail.”

A joint that retains its geometry but shows visible movement under handling or loading.

Slight movement under hand pressure; visible play at pegs or fixings; sometimes a small gap.

Shrinkage of components, loss of fixing integrity or repeated loading may contribute.

• degree of movement
• associated fixing condition
• evidence of past tightening or repair
• implications for the wider assembly

“A loose joint was recorded at the head of the chair leg, with visible movement under light hand pressure.”

A joint that no longer performs its intended function and shows separation or loss of restraint.

Clearly separated components, broken pegs, withdrawn fixings, or fractured tenon shoulders.

Long-term loading, decay at the joint, fixing failure or impact may contribute.

• type of failure observed
• evidence of decay or insect activity at the joint
• associated movement in the wider assembly
• implications for load paths

“A failed joint was recorded at the foot of the principal post, with the tenon separated from the seating.”

Localised crushing of timber at high-load contact points, often perpendicular to the grain.

Dished or compressed surfaces at bearings, sometimes with fibres displaced outwards.

Concentrated loading, undersized bearings or sustained overload may contribute.

• location and extent of crushing
• approximate depth of compression
• any associated movement
• implications for adjacent geometry

“Compression damage was recorded at the bearing of the joist on the wall plate, with approximately 5 mm of crushing.”

Discolouration of timber around iron or steel fixings.

Dark blue-black or rust-coloured staining radiating from nails, bolts or straps.

Reaction between tannins in timber and corroding iron, often in damp conditions, may produce this staining.

• location and extent
• condition of the associated fixing
• evidence of associated decay or softening
• moisture conditions in the vicinity

“Staining from iron fixings was recorded around the strap at the truss heel, with darkened timber extending approximately 40 mm from the fixing.”

Loss of surface material through repeated mechanical contact in use.

Polished, worn or thinned surfaces in handling or traffic zones; loss of original finish.

Use, cleaning regimes, contact with adjacent components or maintenance activity may contribute.

• location and extent of wear
• approximate loss of section
• relationship to use patterns
• implications for adjacent finish

“Surface abrasion was recorded on the handrail in the principal use zone, with a smoothed band approximately 300 mm long.”

Loss of softer earlywood between harder latewood bands on weathered surfaces.

Ribbed or grooved surface following the grain; harder rings standing proud of softer material.

Long-term weathering, especially in unprotected or exposed timbers, may contribute.

• extent and orientation
• depth between rings where assessable
• comparison with sheltered areas
• associated coating loss

“Erosion of exposed grain was recorded on the south-facing rail, with latewood rings standing approximately 1 mm proud of the surface.”

Fibres lifting from the timber surface, producing a roughened texture.

Fine, raised fibres detectable by touch; rough finish under previously smooth coating.

Moisture wetting and drying, aggressive cleaning or coating breakdown may contribute.

• extent and location
• association with moisture exposure
• condition of any overlying coating
• implications for finish performance

“Raised grain was recorded across the weather face of the door, particularly below the panel mouldings.”

Loss of adhesion between veneer and substrate, causing the veneer to lift, blister or detach.

Domed, cracked or peeled veneer; sometimes loss of fragments; sound-hollow response on tapping.

Moisture movement, failure of original adhesive, heat or impact may contribute.

• extent of lifted area
• whether fragments remain in place
• evidence of moisture exposure
• significance of the veneered finish

“Veneer lifting was recorded across the top of the table, with one lifted area approximately 60 mm across.”

Separation of laminated timber into successive layers.

Visible separation along laminations, sometimes with associated glue-line failure.

Moisture, original adhesive performance and stress at laminations may contribute.

• extent of separated laminations
• evidence of moisture exposure
• implications for structural performance
• comparison with adjacent intact laminations

“Delamination was recorded on the lower face of the laminated rafter, with separation along approximately 200 mm of the lowest lamination.”

Loss of integrity of an applied paint, varnish or stain system.

Dull, chalky, thinning or partially lost finish; exposure of underlying timber.

Weathering, UV exposure, age, original preparation or substrate movement may contribute.

• extent of breakdown
• type of breakdown observed
• exposure of underlying timber
• evidence of moisture beneath the coating

“Coating failure was recorded on the upper face of the sill, with the original finish largely lost in exposed areas.”

Raised bubbles within a paint or varnish film, indicating loss of adhesion.

Domed or raised areas in the coating; intact or broken; sometimes containing moisture.

Moisture beneath the coating, application over damp timber or heat exposure may contribute.

• size and distribution of blisters
• whether blisters are intact
• evidence of moisture beneath
• underlying timber condition where visible

“Blistering was recorded on the south-facing face of the door, with several broken blisters exposing the substrate.”

Detachment of paint in flakes or sheets, exposing the substrate.

Lifted, curled or detached paint fragments; exposed timber of varying extent.

Coating failure, underlying movement or inadequate preparation may contribute.

• extent and location of flaking
• size of detached areas
• condition of exposed substrate
• evidence of past repainting cycles

“Flaking paint was recorded on the soffit of the cornice, with exposure of weathered timber beneath.”

An earlier resin or filler repair that appears inappropriate in extent, performance or compatibility.

Visible resin patches; cracking at the interface; differential weathering; loss of moisture mobility around the repair.

Past use of generic fillers, oversized repairs or repairs unsuited to historic timber may contribute.

• extent and location
• condition of the resin and surrounding timber
• evidence of moisture trapping
• significance of the original fabric affected

“An apparently inappropriate resin repair was recorded at the cill end, with cracking at the interface and possible moisture retention behind.”

A previous timber insert that differs significantly from the surrounding fabric in species, grain orientation or condition.

Visibly different colour, grain or texture; mismatched profiles; uneven shrinkage at the interface.

Use of available material rather than matched timber, or past repairs of limited specification, may contribute.

• extent and location
• differences from surrounding fabric
• condition of the insert
• implications for performance and appearance

“An incompatible softwood insert was recorded in the oak frame, with visible shrinkage cracks around the interface.”

An earlier repair that no longer performs as intended.

Cracked, detached, displaced or decayed repair material; evidence of ongoing loss at the repair location.

Movement, moisture, fixing failure or limitations of the original repair design may contribute.

• type of repair affected
• nature of the failure
• associated damage to surrounding fabric
• evidence of recent or historic failure

“A failed previous repair was recorded at the threshold, with the inserted block displaced and the surrounding timber softened.”

A component that was originally present and is now absent.

Empty mortices, voids in mouldings, gaps in assemblies, or visible discontinuity in patterning.

Past damage, loss in service or earlier removal without replacement may contribute.

• location and apparent original function
• evidence of how the element was lost
• implications for performance
• documentary or photographic references where available

“A missing element was recorded at the lower rail, where an original moulded block appears to have been lost without replacement.”

Physical damage from external impact or contact, including dents, gouges and broken edges.

Crushed fibres, broken arrises, gouges, missing fragments; sometimes associated coating damage.

Accidental impact, vehicle contact, maintenance activity or vandalism may contribute.

• type and location of damage
• extent and depth
• any structural implications
• associated coating or surface damage

“Impact damage was recorded at the base of the door, with crushed fibres and loss of coating across an area approximately 80 mm wide.”

Surface darkening or carbonisation of timber from heat or fire exposure.

Darkened, blackened or carbonised surfaces; sometimes with reduced section; characteristic crocodile-skin patterning where deeper.

Direct flame, sustained heat, or proximity to heat sources may contribute.

• extent and depth of charring
• evidence of section loss
• associated structural implications
• any soot deposition on adjacent fabric

“Localised scorch was recorded around the historic flue penetration, with surface darkening but no clear loss of section.”

Damage caused by repeated contact with furniture, equipment or cleaning activity.

Scuffs, marks, grooves and localised wear in defined zones related to use.

Day-to-day use, cleaning regimes and movement of fittings may contribute.

• location and pattern of damage
• evidence of original cause where visible
• extent of wear
• implications for finish and protection

“Accidental abrasion in service was recorded at chair-rail height on the panelling, with scuffs in a band approximately 100 mm wide.”

Discolouration of timber surfaces from rainwater run-off.

Dark streaks following drainage paths; sometimes with associated soiling or biological growth.

Defective gutters, projecting details, lack of drips or run-off from adjacent fabric may contribute.

• location and direction of staining
• associated water pathway
• any softening or decay beneath
• evidence of progression

“Water run-off staining was recorded down the south-facing face of the post, in a pattern consistent with overflow from the gutter above.”

Living organisms colonising timber surfaces or adjacent fabric.

Algae, lichen, moss or plant growth, particularly in sheltered or damp areas.

Moisture retention, sheltered orientation and lack of maintenance may contribute.

• type of growth where identifiable
• extent and location
• association with moisture retention
• any apparent effect on the substrate

“Biological growth was recorded on the upper face of the bench seat, with moss colonising debris in the joint between boards.”

Apparent salt accumulation on timber in marine or coastal exposure.

White or pale crystalline deposits, particularly on sheltered faces; sometimes associated surface degradation.

Wind-driven salt spray, marine atmosphere and sheltered drying conditions may contribute.

• extent and location of deposits
• exposure to marine spray
• associated surface deterioration
• evidence of associated metal fixing corrosion

“Possible salt deposits were recorded on the sheltered face of the cladding, consistent with coastal exposure and prevailing wind direction.”

Non-biological accumulations on timber surfaces from external sources.

Soot, dust, splashed materials or other adhered deposits.

Atmospheric pollution, adjacent activity, run-off or lack of cleaning may contribute.

• type of deposit where identifiable
• extent and thickness
• whether deposits obscure condition assessment
• any associated staining or biological growth

“Surface deposits were recorded on the panelling adjacent to the fireplace, with a dark soiling layer concentrated on horizontal surfaces.”