GLUING SOLID HARDWOOD FLOORS
LAYING INSTRUCTIONS
Commercial / Residential

C 1.3.2

 

C 1.3.2

 


JUNCKERS GLUE DOWN SYSTEM

C 1.0 General
information
C 1.3 Glue Down
System Information
C 1.3.1 Specifier's
Information
C 1.3.2 Laying
Instructions

Fig. 1

BEFORE AND DURING INSTALLING THE FLOOR

The building must be weather tight. The heating system must be installed and tested and during the heating season should be in operation. Cast concrete elements, screeding and other wet trades, which contribute moisture to the building, e.g. tiling, plastering and priming of paintwork, must also be completed.

The relative humidity in the building must be between 35 - 65% RH and the temperature approx. 20° C. The subfloor must have a uniform, firm and clean surface and be sufficiently dry, see section 2 below, which is documented by control measurement. In wooden based subfloors the moisture content should not exceed 12%.

Solid boards should always be laid immediately on their arrival at the building. The packing on the bundles must not be removed until just prior to laying the floor, i.e. no acclimatising of the boards on site must take place.

NB: Read these laying instructions carefully before laying begins.

In case of doubt please contact your Junckers distributor before installing the floor.


1. FLATNESS OF THE SUBFLOOR

The sub-floor must be levelled to a tolerance of no more than 2 mm gap showing under a 1.5 m straight edge (UK: No more than a 3 mm gap showing under a 2 m straight edge).

The surface must be smooth with no roughness. Local irregularities, e.g. above day joints, must be levelled.

To ensure a sufficiently firm and clean surface for optimum adhesion the subfloor should be filled or sanded prior to laying. 


2. MOISTURE PROTECTION

Before laying begins ensure that the residual moisture in the concrete does not exceed 75% RH.

The floor surface is divided into a grid of modules of approx. 5-10 m2 each. The measurements are then taken at each intersection in the grid, using e.g. a capacitive moisture gauge to find the areas with the highest RH. The residual moisture in the areas with the highest RH is then measured using a destructive measuring method, see C 1.3.

Some knowledge and experience of moisture measurement is required for the interpretation and evaluation of the moisture content of a structure. Such measurements should therefore be carried out by an expert.

Use Junckers Liquid Moisture Barrier in case of:

  • The subfloor has a high absorption capacity. A moisture barrier ensures optimum adhesion.
  •  Underfloor heating. The underfloor heating system must be switched off during installation.
  • The allowed maximum residual moisture content is exceeded.

3. APPLYING ADHESIVE

Make sure to choose the correct spatula.

  • Wood based subfloors and concrete subfloors, not necessary to prime with Junckers Liquid Moisture Barrier: Use Junckers plastic adhesive spatula.
  • Floors primed with Junckers Liquid Moisture Barrier: Use Junckers metal adhesive spatula J11.

This ensures leaving the correct amount of adhesive.

The spatula is held at an angle of 45°. Apply 0.5-0.6 litre per m² on an area equivalent to 3-4 rows of floor boards at a time. Never exceed an area in which the floor boards can be fitted within 40 minutes.


4. 10-BOARD MEASUREMENT

Press the floor boards firmly into the wet glue and place the spacers in between every row at a distance of maximum 900 mm in order to achieve the required 10-board measure, 10 BM.

The 10-board measurements noted in the table below state how many millimetres 10 floor boards must cover in width when installing a floor. The measurement must continuously be checked during installation.

 

Type of
spacer

10-board measurement
by different floor board widths

Construction

129mm

140/185 mm

129 mm 

140 mm 

185 mm

Concrete ground floor

0.4mm

0.6 mm

1294 mm

1406 mm

1856 mm

Concrete upper floor

0.2 mm

0.4 mm

1292 mm

1404 mm

1854 mm

Wooden based subfloor

0.2 mm

0.4 mm

1292 mm

1404 mm

1854 mm

Shipsdecking

- *

- *

1298 mm

1408 mm

1858 mm

* Spacers are not used for shipsdecking.

Spacers can be removed and reused, but while installing the floor, make sure always to have spacers placed at a minimum of 3 metres in the laying direction.

This ensures sufficiently drying time of the adhesive.


5. DISTANCE TO WALLS AND FIXED INSTALLATIONS

Expansion gaps to walls and fixed installations must be 1.5 mm per running metre of floor width on each side (A), and 1 mm per running metre of floor length at each end (B), all with a minimum size of 12 mm (UK: 15 mm).

Use temporary spacers or wedges between the wall and the boards to form the expansion gap.


6. FLOOR PATTERN

Lay the boards in a random joint pattern. Distribute the header joints as far apart as possible. The distance between board header joints in two successive rows should be at least 250 mm.

Stave joints in one row of boards should not be in line with stave joints in a neighbouring row, but must be spread as far as possible (min. 50 mm).

Cut the last row of boards to form the correct size of expansion gap at the wall.

Use a joint puller (B) to slot the last board into place. Remove temporary spacers or wedges before installing skirtings.


7. PIPES, DOOR FRAMES, THRESHOLDS

Around pipes, drill a hole in the board to accommodate the pipe. The space around the pipe must be the same as the expansion gap at the wall.

A tapered wedge is cut out, so that it can be glued in place. This gap is covered using a radiator pipe cover.

At door frames and architrave’s, cut the base of the frame and architrave to allow the floor to fit underneath.

At the threshold the expansion gap can be covered by a threshold strip or, if levels reduce, fit a ramp.

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