It's not you: the floor really is crooked

You have arrived at your dream apartment, modern and renovated, just as the listing said. The kitchen is nice, the rooms too, but wait, the floors have color differences... Small thing, sure, and the apartment still looks great overall, but the flaw is enough to keep you up at night...

Building inspection of stone floors

Buying an apartment is a big decision, and the small details matter just as much as the big ones.

The walls in that lovely apartment are freshly plastered and the rooms really are spacious, but the color differences in the tiles tell a different story: maybe a pipe burst there and got patched up, or maybe someone did a quick cosmetic fix before putting the apartment up for sale. Either way, you need to know which it is.

This is exactly what a building inspection is for: a full review of the apartment's condition, including whether the tiles were laid and bonded correctly, the grout is sound, and the work throughout meets a high standard.

This is a real aesthetic flaw, so it pays to stay alert, and more importantly, it can be hiding a bigger problem: a pipe leak that turns into a costly repair.

The major sinking issue

Another flaw that turns up often is a sunken floor. Tiling is a craft, and whether you are buying a new apartment from a contractor or renovating a resale one, it matters that the person doing the work is a genuine professional. As with everything else here, there is a standard that governs it.

Here are some of its main points:

• Lime must not be used in the mortar bed under the tiles.

• Gray cement must not be used.

• Broken or cracked tiles must be sorted out and removed.

• When cladding, the gaps between the tiles must be filled with grout to keep water out and stop the substrate from settling.

• Before use, the tiles must be protected from dust, rain and other damage.

• Skirting boards must match the tiles in shade and type.

• After tiling, the surface should be covered to protect it from building materials and dirt.

• An initial stone polish, about a week after tiling, removes cement residue.

• A final polish follows later, along with filling any grout gaps still left open.

• Once the work is done, an anti-absorption, anti-staining and polishing treatment is recommended.

Building inspection: choosing the tiling

You may not know this, but any building inspection engineer will tell you to demand these details from the contractor before buying a new apartment or starting a renovation:

· See samples of every tile type before work starts, and compare them to what actually arrives on site.

· See certificates proving the tiles carry a standards mark and a recognized manufacturer's marking.

· Keep the samples somewhere they cannot be swapped or relabeled.

· Make sure the tiles match what was agreed with the architect and the specification or bill of quantities.

· Check that the materials carry a standards mark stating the type of material, abrasion resistance, weight per square meter, breaking load and cement content in the wearing layer.

· Check the tile surfaces to make sure they are smooth and free of flaws.

To avoid surprises, put an agreement in writing with the contractor doing the work that sets the total cost, the schedule, the warranty, and prices with and without materials.

A building inspection will also reveal other flaws related to the tiling: stains, chips, or tiles of different sizes.

So next time you think the floor is crooked, know this: it's not you, the floor really is crooked.

This article was written in collaboration with engineer Ron Arad

Arad Bedek Bayit