Marmoleum, a natural product, is closer to timber in composition than a vinyl. Marmoleum is a truly natural sustainable resilient and modular floor that is manufactured Carbon Neutral (cradle to gate). More CO2 is absorbed in the growing phase of the raw materials, linseed, wood flour and jute than CO2 released from the production process. Simply put, as long as the sun shines and the rain falls, Marmoleum can be produced.
Like timber and other natural products Marmoleum has some unique characteristics that are useful to understand and will make a world of difference when installing. In this edition we will focus on seams and welding.
To weld or not to weld?
Marmoleum contains ZERO PVC or plastic and will not shrink at the seams over time. Hessian backed Marmoleum shrinks slightly in the length (1mm per lineal metre) stretches slightly in the width (thickness of a credit card or business card) during installation. This means that a well-cut seam will close tightly by the time the adhesive has cured to bond the linoleum in its final and fixed position. A correctly cut seam will not open or expand during the life of the linoleum and is often considered to be aesthetically nicer than a welded seam, normal cleaning routines will not affect the joins. As long as you or the installer can cut and scribe a good seam, and if the application allows, welding of Marmoleum is not obligatory and not suggested by Forbo. Marmoleum tiles and planks have a polyester backing and never need to be welded, a great option for residential.
If there is a requirement to weld the sheet seams (e.g. childcare) most installers are accustomed to welding sheet PVC vinyl floors. Marmoleum is very similar with some minor adjustments. The composition of linoleum weld cable requires a different welding temperature and speed. This is because Marmoleum weld is a different formulation to bond with timber/linseed as opposed to PVC. Problems encountered with welding are usually due to either welding at the high temperature and/or speed or use of incorrect weld and trimming techniques. The correct grooving tool and depth must also be used. A P groover must be used, never use a triangular grooving tool. The depth should be 2/3 thirds deep or just above the hessian backing.
Marmoleum should be welded at a temperature of approximately 300-350° C. Weld guns will vary, so it is always advisable to test on a piece of waste material to match the correct air gun temperature with welding speed. The weld cable should be trimmed whilst warm using a spatula and slide, which will leave the weld cable approximately 0.5mm proud of the surface of the linoleum. A Mozart knife can also be used. As with vinyl, the weld cable will dish slightly as it cools. Wait until the material is cool before trimming the remaining surplus weld cable using a spatula angled slightly across the line of the seam. Where vinyl sheet floor covering meets Marmoleum always use Marmoweld weld cable.
NB: Attempting to trim the weld cable flush with the floor covering in one operation will often result in the weld cable being pulled out of the seam resulting in avoidable re-welding of the seam.
Seam Hints: Fit and finish one run at a time, do not pull back and glue up multiple runs as this can be hard to judge the amount of lateral width expansion gap needed.
Note: Once the Marmoleum is correctly bonded to the subfloor shrinkage in the length of the sheet and lateral expansion in the width of the sheet will no longer take place. The recess scriber being adjusted with a small gap the thickness of a credit/business card. Marmoleum seam peaking and is usually attributed to the seam being recess scribed too tight or lack of adhesive and rolling.
The appearance, performance and durability of the installed floorcovering will be determined to a large extent by the quality of the prepared subfloor and the conditions in which they are laid.
Pictured: Net fit seams no weld (left) and welded Marmoleum with matching mutli-colour weld