John Boos CU-SB2424-BN Leaflet

Correct installation of JOHN BOOS BUTCHER BLOCK COUNTER TOPS is vital for 
optimum performance.

The moisture content of butcher block will vary due to the movement of moisture into and 
out of the wood.  Natural humidity (dry and wet), air conditioning, machines that dispel heat 
or moisture (eg. Dishwashers, cooking appliances, etc.) will affect the moisture content of 
the wood.  As moisture in the air increases it is absorbed by the butcher block, and the wood 
will expand.  The butcher block contracts as moisture in the air decreases.

BUTCHER BLOCK, being a natural wood product, will expand and contract across the 
grain with these changes in humidity.  This movement is quite normal.  It is usually only 
minimal and can be allowed for in the installation (see Figure 3).

Good sealing is essential to prevent an abrupt and excessive moisture movement to and 
from the wood.  BUTCHER BLOCK must be envelope sealed, ie: top, bottom, edges and 
ends.  Pay particular attention to the inside of cutouts, especially the end grain.  If you cut 
on site – reseal the cut area with at least four (4) coats of sealer.

Minimal fixing only is required as the piece will be 
held down by self weight, plumbing, etc.  Ideally, 
fix into the same strip of wood.  Slotting or 
oversized holes will also help.  The diagrams at 
right show examples of correct or incorrect fixing.

 

John Boos tops are suitable for interior use only.

Dishwashers, floor mounted vents and hot water systems.
Where appliances have heat acting on the bench top, polystyrene or similar insulation 
should be installed to cut down heat transference.  Provide adequate ventilation.

Sinks, cooktops, cutouts for posts, etc.
The fitting of sinks, basins, cooktops, etc. must not restrict the bench top from expanding 
and contracting.  Ensure that there is at least one quarter inch (1/4”) clearance all around the 
appliance.  Insulation should be installed around cooktops.  Rubberized joint sealant should 
be used in sink and basin applications.

Vegetable storage.
Where vegetables or other material that are likely to give off moisture are stored under the 
counter, insulation should be installed and adequate ventilation provided.

Ventilation.
Particle board or MDF tops fixed to cabinets should be removed or have large holes cut into
them to assist with even and adequate ventilation.  Do not attach directly on top of a solid
underlayment.  Butcher block needs adequate ventilation.

Brick walls.
A moisture barrier, such as plastic, should be utilized in situations where “BUTCHER
BLOCK” is located adjacent to brickwork or rendered walls to prevent moisture transference.
A slight air gap should also be left.

Overhangs.
If overhangs exceed eight inches (8”), then some form of bracketing should be used for support.

Fixing through framework into the underside of 
bench should be via a 7/16” clearance hole and a 
#10 gauge screw with washer, allowing movement 
between fixing points.  Holes should be predrilled.

NOTE: Ensure screw is centralized within 
clearance hole.

To ensure optimum performance, BUTCHER BLOCK requires protection from the
environment by means of seal coatings.  Sunlight breaks down most coatings, exposing the
timber and allowing moisture, humidity and heat to act

Being a natural product, your tops are subject to changes in atmospheric conditions, and
therefore require some care in handling and storage.

JOHN BOOS BUTCHER BLOCK COUNTER TOPS are warranted free from manufacturing
defects, and the performance of the product is guaranteed, providing the conditions relating to
handling and storage are adhered to and that fabrication and installation has been performed to
John Boos recommendations.

Natural wood features and variations in color and texture of the wood and/or laminates are not
considered defects.

All edges to be joined together must be dressed true (exact).  The recommended
corner joints are MITER joints or full BUTT joints.  With miter joints on boards of
unequal width, a true miter usually gives the best result as any movement is
equalized, and the laminates will be close to matching at the joint.

1.1: Biscuit or tongue the joint.  Joints should have “Lamella” biscuits or plywood 
slip tongues fitted.

1.2: Bolt clamp the joint.  Do not use dowels.  Fit bolt clamps (miter bolts) to 
the underside of all joints; 4” from the front, 6” from the back of miters and 
1-1/2” from both sides of butt joints.  On wide joints fit an extra clamp midway 
between the others.

1.3: Butt joints with opposing grain direction are never to be glued, instead use 
silicon.

1.4: Miter joints and butt joints with grain running in the same direction 
should be glued.

Fitted to the front edges of bench tops.  Must not be glued across the grain.  If 
an apron is to run across the end of the bench top, it should be screwed with a 
fixing baton, allowing for movement, or “build up” the end grain by slicing off 
sections of the bench top end and gluing underneath. 

On receipt of your John Boos tops, it is essential that they are to be stored in a way that 
they are protected from the weather and areas that are subject to extreme changes in 
humidity.  Store flat at least 8” off the floor to allow air to circulate.  Do not leave boards 
leaning against brick or concrete walls as excess moisture pick up is inevitable.
It is essential that BUTCHER BLOCK is fully envelope sealed as soon as possible with at 
least four coats.

nd Splitting:  is common with unsealed boards.  Repair by filling with Epoxy glue.

Minor Wood Defects:  Natural to butcher block.  Can be repaired with Wood Putty colored 
to suit.

Use full strength Epoxy glues for like grain directions and Silicon sealant 
wherever there is opposing grains.

Must have a 3/16” clearance on all sides and corners should have a slight radius. 
The distance between the end of the bench top and a cutout or between cutouts 
should be at least 4-5”.  If this is not possible, reinforce the narrow cross grain 
section by recessing and bluing a piece of similar John Boos butcher block into 
the underside with the grain running in the same direction and position it so that 
the glue lines are offset to the glue lines on the bench top.

A rubberized joint sealant should be used in all sink and basin applications. 
Holes must be properly sealed with at least four coats of polyurethane. 
Particular attention should be paid to the end grain.

Any grain checking, tear-out and similar butcher block blemishes should be 
filled and sanded (use a wood putty).  Shakes, which have a tendency to lift, 
should be repaired with “5 minute" Epoxy colored to match the wood.

6. SANDING.

Sand the surface and seen edges through a suitable range of papers.