How to produce a firm bond

The floor­ing bends under your feet and a hol­low sound can be heard – obvi­ous signs of improp­er floor­ing install­a­tion. These prob­lems are often due to poor pre­par­a­tion of the sub­strate. Without expert pre­par­a­tion, the floor­ing installed on top will be affected and even suf­fer dam­age in the long run – regard­less of the mater­i­al. The con­sequences range from noise gen­er­a­tion (impact sound) all the way to bumps and cracks.

When repla­cing the old floor cov­er­ing in the course of a renov­a­tion pro­ject, it is recom­men­ded to thor­oughly check the sub­strate. Five cri­ter­ia need to be con­sidered: even­ness, dry­ness, strength, free­dom from dirt and cracks. If, for example, the sur­face is of insuf­fi­cient strength, there will be no firm bond between sub­strate and adhes­ive resp. adhes­ive and floor cov­er­ing. But how can the strength reli­ably be tested? Pro­fes­sion­al floorers recom­mend the so-called scratch test. With a sharp met­al object, a grid of scratch lines is applied. If there is no flak­ing along the line edges, the sub­strate is of suf­fi­cient strength.

Just as import­ant is the level­ness or even­ness of the sub­strate. If there are cav­it­ies or hol­lows, hard floor­ing mater­i­als such as tiles, par­quet and lam­in­ate can break. Cav­it­ies also gen­er­ate unpleas­ant foot­fall sound and trans­fer the heat of under­floor heat­ing sys­tems less effect­ively. Even though resi­li­ent cov­er­ings like car­pets and PVC are to a cer­tain degree able to adapt to uneven sub­strates, this is not a pretty sight. You should also make sure that the sub­strate is abso­lutely dry. Mois­ture impairs the adhes­ive bond and can also pro­mote mold growth. New screeds in par­tic­u­lar often have a high con­tent of resid­ual mois­ture that needs to be checked – but bet­ter leave that to an expert.

Before the new floor­ing is glued in place, the sub­floor must be cleaned of dirt. This also includes adhes­ive or oily residues. To ensure optim­um adhe­sion, the sub­strate should be swept and vacu­umed again to remove the last particles of dirt and dust. If, for example, par­quet is to be laid, experts recom­mend apply­ing a coat of dis­per­sion primer. Care­ful sub­strate pre­par­a­tion is cru­cial if you want to make the most of your newly installed floor in terms of beauty and func­tion. There is a wide range of suit­able build­ing and install­a­tion products avail­able for this pur­pose