Parquet Floor Restoration in London Victorian Homes: Sanding, Finishing, and Herringbone Repair Guide

TRADITIONAL VICTORIAN BLOCK PARQUET INSTALLED IN LONDON TERRACES FROM THE 1870S TO 1930S IS A SOLID HARDWOOD FLOOR LAID IN A PATTERN OF SMALL RECTANGULAR BLOCKS DIRECTLY ONTO A SUBSTRATE. THE CHARACTERISTICS OF AUTHENTIC VICTORIAN BLOCK PARQUET ARE AS FOLLOWS.

BLOCK DIMENSIONS: TYPICAL BLOCKS ARE 70MM TO 90MM WIDE AND 230MM TO 250MM LONG, AT 22MM TO 28MM THICKNESS (MUCH THICKER THAN MODERN ENGINEERED PARQUET). THE THICKNESS MEANS ORIGINAL VICTORIAN PARQUET CAN BE SANDED MULTIPLE TIMES — A WELL-MAINTAINED ORIGINAL FLOOR WITH THREE OR FOUR PREVIOUS SANDS STILL HAS SIGNIFICANT MATERIAL REMAINING.

TIMBER SPECIES: THE MOST COMMON SPECIES IN LONDON VICTORIAN PARQUET IS PITCH PINE (PINUS RIGIDA / PINUS PALUSTRIS — IMPORTED FROM THE AMERICAN SOUTH), FOLLOWED BY OAK (QUERCUS ROBUR — EUROPEAN OR ENGLISH OAK), BEECH (FAGUS SYLVATICA), AND OCCASIONALLY IROKO OR TEAK IN HIGHER-VALUE PROPERTIES. PITCH PINE PARQUET HAS A DISTINCTIVE ORANGE-AMBER COLOUR WITH PROMINENT FLAME GRAIN AND FINE RESIN CANALS — IT IS HARDER AND MORE RESINOUS THAN OAK AND RESPONDS DIFFERENTLY TO SANDING AND FINISHING.

LAYING PATTERNS: THE MOST COMMON PATTERN IN LONDON VICTORIAN TERRACES IS THE HERRINGBONE (ALTERNATING 90-DEGREE BLOCKS IN A V-PATTERN). BASKET WEAVE (GROUPS OF PARALLEL BLOCKS ARRANGED PERPENDICULAR TO ADJACENT GROUPS) AND BRICK BOND (STAGGERED RECTANGULAR BLOCKS LIKE BRICKWORK) ARE ALSO SEEN. STRIP PARQUET (STRAIGHT-LAID NARROW STRIPS) APPEARS IN LATER EDWARDIAN AND INTER-WAR PROPERTIES.

SUBSTRATE: VICTORIAN BLOCK PARQUET WAS TYPICALLY BED-SET IN BITUMEN/PITCH ADHESIVE ON A TIMBER BOARDED SUBSTRATE (OVER JOIST FLOOR), OR OCCASIONALLY DIRECTLY ON A MORTAR SCREED IN GROUND-FLOOR ROOMS. THE BITUMEN ADHESIVE LAYER IS ONE OF THE KEY CHALLENGES IN PARQUET RESTORATION — IT IS VERY DIFFICULT TO REMOVE AND MUST BE MANAGED RATHER THAN ELIMINATED IN MOST CASES.

BEFORE COMMITTING TO A PARQUET RESTORATION PROJECT, A CAREFUL ASSESSMENT OF THE FLOOR CONDITION IS REQUIRED.

FLOOR ASSESSMENT CHECKLIST: MOVEMENT — ARE BLOCKS LOOSE OR ROCKING? LOOSE BLOCKS MUST BE RE-ADHERED BEFORE SANDING. TAP EACH BLOCK WITH A RUBBER MALLET — A HOLLOW SOUND INDICATES DEBONDED ADHESIVE BENEATH. CUPPING — HAVE BLOCKS CUP (CONCAVE ACROSS THE WIDTH) DUE TO MOISTURE IMBALANCE? MILD CUPPING CORRECTS ITSELF ONCE HUMIDITY IS CONTROLLED AND SANDING LEVELS THE SURFACE. SEVERE CUPPING INDICATES ONGOING MOISTURE ISSUE (CHECK SUB-FLOOR VENTILATION AND DAMP).

BREAKAGE AND MISSING BLOCKS — ARE THERE CRACKED OR BROKEN BLOCKS? ARE ANY BLOCKS MISSING? REPLACEMENT BLOCKS IN THE ORIGINAL SPECIES AND DIMENSIONS ARE AVAILABLE FROM SALVAGE COMPANIES — TIN TIN ANTIQUES AND MARKETS (CAMBERWELL), LASSCO (WATERLOO), AND DRUMMOND'S (CHICHESTER) FOR OAK AND PITCH PINE BLOCKS IN LONDON PERIOD DIMENSIONS. WHERE EXACT MATCHES ARE UNAVAILABLE, STRATEGICALLY SOURCED MISMATCHES CAN BE PLACED IN AREAS THAT WILL BE UNDER FURNITURE.

BITUMEN CONTAMINATION — IN GROUND-FLOOR ROOMS WHERE THE BITUMEN ADHESIVE HAS DEGRADED AND RISEN INTO THE LOWER FACE OF THE BLOCKS (PARTICULARLY WITH PITCH PINE), DARK BITUMEN STAINING MAY APPEAR AFTER SANDING. THIS IS ONE OF THE MOST FRUSTRATING ASPECTS OF VICTORIAN PARQUET RESTORATION — THE BITUMEN CANNOT BE FULLY REMOVED BY SANDING AND CAN BLEED THROUGH OIL FINISHES. APPLYING A SHELLAC SEALANT (ZINSSER BULLS EYE SHELLAC) AS A PRIMER BEFORE THE FINISH COAT BLOCKS BITUMEN BLEED.

FLOOR HEIGHT — IS THERE SUFFICIENT MATERIAL REMAINING FOR SANDING? THE MINIMUM RECOMMENDED MATERIAL ABOVE THE TONGUE (WHERE BLOCKS HAVE A TONGUE AND GROOVE JOINT) IS 4MM. IF THE FLOOR HAS BEEN SANDED CLOSE TO THIS LIMIT, ONLY LIGHT SANDING WITH FINE GRIT IS POSSIBLE.

FLOOR SANDING IS A SKILLED TRADE — AGGRESSIVE SANDING ERRORS (SANDING ACROSS THE GRAIN OF HERRINGBONE PARQUET, DRUM MARKS, OVER-SANDING) ARE DIFFICULT TO CORRECT AND CAN RUIN AN ORIGINAL FLOOR. PROFESSIONAL FLOOR SANDING CONTRACTORS USING PROFESSIONAL EQUIPMENT CONSISTENTLY PRODUCE BETTER RESULTS THAN DIY APPROACHES, AND THE COST OF PROFESSIONAL SANDING IS SMALL RELATIVE TO THE RISK OF DAMAGING A VALUABLE ORIGINAL FLOOR.

EQUIPMENT USED BY PROFESSIONALS: BONA BELT SANDING MACHINE (BONA BELT OR BONA SCORPION) FOR FIELD SANDING — A LARGE ROTARY DRUM OR BELT SANDER THAT COVERS THE MAIN FLOOR AREA. BONA EDGE SANDER OR LAGLER FLIP FOR PERIMETER SANDING WITHIN 150MM OF THE WALL. BONA MULTI FOR AWKWARD CORNERS AND TIGHT AREAS.

SANDING SEQUENCE FOR HERRINGBONE PARQUET: HERRINGBONE PARQUET IS SANDED AT 45 DEGREES TO THE BLOCK DIRECTION (DIAGONALLY TO THE HERRINGBONE PATTERN) FOR THE FIRST ROUGH GRIT PASS, THEN AT THE OPPOSITE 45-DEGREE DIRECTION FOR THE SECOND PASS, THEN FINALLY ALONG THE PRINCIPAL DIRECTION OF THE PARQUET PATTERN FOR THE FINISHING PASSES. THIS SEQUENCE MINIMISES CROSS-GRAIN SCRATCHING WHILE ACHIEVING A LEVEL SURFACE.

GRIT SEQUENCE: TYPICAL GRIT SEQUENCE FOR A RESTORATION SAND IS: 24 GRIT (ROUGH CUT — REMOVING OLD FINISH AND LEVELLING HIGH BLOCKS); 40 GRIT (SECOND PASS, REMOVING 24 GRIT SCRATCHES); 60 GRIT (INTERMEDIATE SMOOTHING); 80 GRIT (PRE-FINISH SMOOTHING); 100 OR 120 GRIT (FINAL PASS — FINISH READY). FOR A PARQUET THAT IS STRUCTURALLY SOUND AND PREVIOUSLY OILED (RATHER THAN LACQUERED), THE INITIAL GRITS MAY START AT 40 AND PROGRESS TO 120 WITHOUT THE VERY COARSE PASSES.

DUST EXTRACTION: PROFESSIONAL DUST-FREE SANDING USING THE BONA DUST CONTAINMENT SYSTEM (INTEGRATED BAG ON THE DRUM SANDER CONNECTED TO A HEPA-FILTERED VACUUM) IS STRONGLY RECOMMENDED TO PROTECT THE PROPERTY AND ITS OCCUPANTS FROM SANDING DUST, WHICH CONTAINS FINE HARDWOOD PARTICULATES AND POTENTIALLY RESIDUAL OLD LEAD-BASED PAINT FROM PRE-1960S FLOOR FINISHES.

GAPS BETWEEN PARQUET BLOCKS ARE COMMON IN RESTORED FLOORS DUE TO THE NATURAL SHRINKAGE OF SOLID HARDWOOD OVER 100 YEARS. THE CORRECT GAP-FILLING METHOD DEPENDS ON THE GAP SIZE AND THE SPECIFICATION OF THE FINISH.

SMALL GAPS (UNDER 2MM): MIX FINE SANDING DUST FROM THE FIRST SANDING PASS (THE DUST COLOUR PERFECTLY MATCHES THE FLOOR) WITH AN APPROPRIATE ADHESIVE. FOR OILED OR HARDWAX-OIL FLOORS: MIX DUST WITH BONA MIX FILLER, LOBA WATERBORNE FILLER, OR BLANCHON WATER-BASED FILLER TO FORM A PASTE. APPLY WITH A RUBBER SCRAPER, PRESSING INTO GAPS, ALLOW TO DRY, AND SAND FLUSH.

LARGER GAPS (2MM TO 8MM): TWO-PART EPOXY FILLER (BONA TRAFFICLINE FILLER OR BLANCHON TWO-PART FILLER) MIXED WITH FLOOR DUST PROVIDES A STRONGER, MORE DURABLE FILL FOR LARGER GAPS THAT ARE SUBJECT TO MOVEMENT. FOR GAPS OVER 8MM, SLIPS OF MATCHING HARDWOOD CAN BE CUT AND GLUED IN PLACE AS SOLID INFILLS.

GAP-FILLING PHILOSOPHY: SOME CUSTOMERS PREFER TO LEAVE GAPS UNFILLED, AS GAP-FILLED FLOORS CAN SHOW CRACK LINES WHERE SEASONAL WOOD MOVEMENT CAUSES THE FILL TO SHRINK FROM THE EDGES. THIS IS PARTICULARLY RELEVANT IN PITCH PINE FLOORS WHERE THE WOOD IS MORE DIMENSIONALLY STABLE THAN OAK BUT STILL MOVES SEASONALLY. THE BEST OUTCOME FOR UNFILLED FLOORS IS TO OPTIMISE THE INTERIOR RELATIVE HUMIDITY TO A STABLE 45 TO 55% RH YEAR-ROUND TO MINIMISE SEASONAL MOVEMENT.

THE CHOICE OF FLOOR FINISH DETERMINES THE AESTHETIC, THE MAINTENANCE REQUIREMENTS, AND THE LONG-TERM DURABILITY OF THE RESTORED PARQUET. THE TWO MAIN FINISH TYPES FOR RESIDENTIAL LONDON PARQUET FLOORS ARE HARDWAX OIL AND WATER-BASED LACQUER (SEAL).

HARDWAX OIL (BONA HARDWAX-OIL RAPID, OSMO POLYX-OIL, PALLMANN MAGIC OIL, RUBIO MONOCOAT): A PENETRATING FINISH THAT SOAKS INTO THE WOOD FIBRES RATHER THAN FORMING A SURFACE FILM. AFTER CURING, THE WAX COMPONENT HARDENS IN THE WOOD PORES, GIVING A NATURAL, MATTE-TO-SATIN APPEARANCE THAT FEELS AND LOOKS LIKE THE NATURAL WOOD SURFACE. HARDWAX OIL FINISHES: LOOK MORE NATURAL AND SHOW THE WOOD GRAIN AND CHARACTER WITHOUT A PLASTIC FILM; ARE EASIER TO SPOT-REPAIR (A DAMAGED AREA CAN BE RE-OILED WITHOUT RE-SANDING THE WHOLE FLOOR); ARE MORE RESISTANT TO WATER PENETRATION AND LOCALISED STAINING THAN LACQUERS; REQUIRE PERIODIC MAINTENANCE — A MAINTENANCE OIL APPLICATION (BONA RICH REFRESHER, OSMO WOOD REVIVER OIL REFRESHER) EVERY 1 TO 3 YEARS DEPENDING ON TRAFFIC. OSMO POLYX-OIL EFFECT PROVIDES A SATIN OR MATT FINISH WITH ENHANCED SURFACE PROTECTION AND IS ONE OF THE MOST POPULAR CHOICES FOR LONDON PERIOD HOMES.

WATER-BASED LACQUER (BONA TRAFFIC HD, PALLMANN EASY FINISH, LOBA 2K INVISIBLE, WOCA MASTERCOLOR): A SURFACE-FORMING COATING THAT CURES TO FORM A DURABLE PROTECTIVE FILM OVER THE WOOD. WATER-BASED LACQUERS: ARE MORE SCRATCH-RESISTANT THAN HARDWAX OILS IN HIGH-TRAFFIC AREAS; GIVE A CLEANER, UNIFORM APPEARANCE (PARTICULARLY USEFUL WHERE COLOUR VARIATION BETWEEN BLOCKS IS MARKED); ARE EASIER TO CLEAN WITH CONVENTIONAL FLOOR CLEANERS; CANNOT BE SPOT-REPAIRED — A WORN LACQUER FLOOR MUST BE FULLY SANDED AND RE-LACQUERED. BONA TRAFFIC HD TWO-COMPONENT IS THE PROFESSIONAL STANDARD HIGH-TRAFFIC LACQUER IN THE UK — APPROXIMATELY 3.5 TIMES MORE ABRASION-RESISTANT THAN STANDARD WATER-BASED LACQUERS (TABER TEST CS17 WHEEL 500G CYCLES).

FOR NEW EXTENSION OR RENOVATION SPACES WHERE AN ORIGINAL PARQUET DOES NOT EXIST, ENGINEERED OAK HERRINGBONE PARQUET IS THE MOST POPULAR CONTEMPORARY FLOORING CHOICE IN LONDON PERIOD HOMES, PROVIDING THE VISUAL CONTINUITY WITH ORIGINAL FEATURES WHILE OFFERING BETTER DIMENSIONAL STABILITY OVER UNDERFLOOR HEATING.

ENGINEERED OAK HERRINGBONE PARQUET SPECIFICATIONS: THE STANDARD ENGINEERED HERRINGBONE PARQUET SPECIFICATION FOR LONDON RESIDENTIAL RENOVATION IS: 70MM WIDE X 280MM LONG X 14MM TO 15MM TOTAL THICKNESS, WITH A 3.0MM TO 4.0MM SOLID OAK WEAR LAYER ON A BIRCH PLY CORE (5-PLY OR 7-PLY). THE BIRCH PLY CORE IS DIMENSIONALLY STABLE ACROSS MOISTURE VARIATIONS, MAKING ENGINEERED OAK SUITABLE FOR INSTALLATION OVER UNDERFLOOR HEATING (UFH) — SOLID OAK WOULD EXPAND AND CONTRACT TOO MUCH SEASONALLY OVER UFH.

BOARD SOURCES IN LONDON: TED TODD HOUSE OF TED (PREMIUM, BRUSHED AND OILED OAK, MULTIPLE WIDTHS), HAVWOODS (HW6065 HERRINGBONE, POPULAR GREY-OILED FINISH), BOEN 138MM HERRINGBONE (LIVE PURE FINISH), QUICK-STEP DISEGNO HERRINGBONE (LACQUERED, COST-EFFECTIVE), AND V4 WOOD FLOORING TUNDRA PLANK HERRINGBONE.

INSTALLATION: ENGINEERED HERRINGBONE PARQUET IS GLUED FULLY TO A PRIMED, FLAT SUBSTRATE (ANHYDRITE SCREED OR PLYWOOD LAYER OVER JOIST FLOOR) USING A SINGLE-COMPONENT MOISTURE-CURE PARQUET ADHESIVE (BONA R848 PROFESSIONAL, SIKA SIKAFLOOR-400 N MULTIBOND, BOSTIK BST SELECT). THE SUBSTRATE MUST BE FLAT TO ±3MM IN 2M BEFORE INSTALLATION — HIGH SPOTS SHOULD BE GROUND DOWN AND LOW SPOTS FILLED WITH BONA FILLER OR ARDEX K79 SMOOTHING COMPOUND. THE LAYING PATTERN STARTS FROM A CENTRE DATUM LINE TO ENSURE SYMMETRICAL PATTERN IN THE ROOM.