Solution to site problems

Discolouration of wall grout Can be any colour, if the grout is darker then it will appear as a white residue on the surface if the grout is white it will appear as a yellow residue on the surface.

What does it look like? Light coloured grout will go yellow or brown

What is the cause Can be caused by shampoo or house hold cleaners Biggest cause is moisture trapped in the substrate The moisture slowly evaporates through the grout If it is caused by shampoo then it will likely be a brighter colour. If it is caused by moisture trapped behind the tiles then the fixer has usually tiled on to plaster that still contained moisture, the British Standard states that 2 coat plaster should be allowed to dry for 4 weeks prior to tiling and that skimmed plaster should be left for 2 weeks. Another possibility is that if they used ready mixed adhesive they grouted before the adhesive was properly dry, ready mixed adhesive must be left for a minimum of 24 hours before it is grouted.

What is the cause Best option is to remove the grout Once the substrate has dried the joints can be re-grouted If it is not possible to wait weber.joint pro should be used If they will not remove the grout there are grout restorers they can apply over the top, the best one being grout rescue by Universeal, this product must be treated with care as it can become stuck to the surface of the tile and they do this at their own risk. Our preferred choice is to remove the grout and re-grout.

Dot and dab incorrect application This is usually down to poor preparation of the background, where the back ground is too uneven to make up by using a trowel. More common on walls because the tile sizes have become to big for the usual flatness of a wall and the tile fixer doesn’t know how to rectify this. Completely against all standards and is never acceptable, doesn’t bond with the background correctly, and if only 25% of the tile is covered where the standard might insist on 95%+ you have effectively made the adhesive a quarter as strong as it should be.

What does it look like The tile backs and substrate will have four or five rounded columns of adhesive with substantial air voids in between

What does it look like Spots of adhesive can be seen through the tile This is a natural stone, adhesive always bleeds through a natural stone and this is why white adhesive is usually used, when fixing stoke they should spread the adhesive on the floor as normal and put a thin layer of adhesive on the back of the tile to ensure the adhesive shows though the tile evenly.

What does it look like? Tiles crack in areas that are unsupported due to point loads such as heels or furniture On a floor it can lead to the tiles becoming cracked because there is nothing supporting the tile underneath, remember the ideal on a floor is to have 100% coverage of adhesive behind the tile. If you suspect this is the cause of the failure then give the tiles a tap with a coin, if it sounds hollow then there is no adhesive under that part of the tile.

What is the cause Poor preparation Background is very uneven Puts to much pressure on the adhesive Voids cause various problems A background should not vary more that +-3mm under a 2M straight edge and preparation is the key, with large format floor tiles weber.floor flex should almost always be used.

What is the remedy? Difficult to remove the tiles and adhesive without damaging the background If floor prime background and old adhesive with PR360 Cover floor with weber.floor flex For walls it can be easier to replace the boards On walls lots of work may be required to get the wall to the correct standard. On floors you can cover any old adhesive residue with weber.floor flex

No movement joints Standards for movement joints Wall Tiling Over existing structural joints, where tiling abuts other materials, where there is a change in background, internal vertical corners, at 3 to 4.5M centres, if large amounts of movement are expected this frequency may need to be increased and advice should be sought. Floor Tiling Over structural movement joints, over supporting walls and beams where deflection might occur, at floor perimeters, dividing into bays not larger than 10m x 10m, at changes in background, around columns, at openings Heated floors With under floor heating where porcelain or ceramic tiles are being used the panel size should be 40m2 i.e. 8 X 5 m Where agglomerate or resin tiles panel sizes should be 25m2 i.e.5 x 5m With regards to commissioning the under floor heating The screed should be allowed to dry in the normal way and then the temperature of the water turned up by 5 degrees a day to maximum water temperature of 45 degrees, kept at that level for 3 days and then allowed to return to room temperature, in cold weather the floor should be at 15 degrees before tiling commences.

What does it look like? Tiles can crack in many different patterns, become loose or in extreme cases form a bridge Often cracking will be noticed originating from stress points such as corners and doorways

What is the cause? Tiles can expand with heat and press against walls etc In large areas pressure can develop between substrate and tile 2 Different substrates meet

What is the cause? All damaged tiles should be replaced and suitable movement joints fitted as stated in BS 5385 In extreme cases it may be necessary to remove all the tiles and replace with adequate provision for movement joints The tiles should be removed and movement joints installed.

What is the cause? Flexible movement joints should be incorporated: Where tiling meets other materials (e.g. flooring perimeters) Along all internal corners — vertically and horizontally

What is the cause? Where flexing is likely on suspended floors (e.g. over supporting beams) Over existing movement joints or changes in background material

What is the remedy Dividing large tiled areas into bays (3 — 4.5m on walls, 8 — 10m on floors) Note: Heated floors should be split into bays not greater than 40m² with an edge length no greater than 8m. More sensitive tiles should be split into bays of 25m2

De-bonding on anhydrite screeds Anhydrite screeds when they cure form a weak surface layer this must be removed by abrading with a sand paper. Floor must then be vacuumed Before tiling commences the floor must be saturated with PR360 diluted 3 parts water 1 part primer, at least 2 coats but must be done until the floor will not accept more primer. There are no exceptions to this even if the screed company claim that the screed is low laitance.

What does it look like The adhesive will come away from the substrate and often a layer of laitance will still be adhered to the adhesive. In extreme cases the adhesive will become very crumbly

What is the cause Failure in removing the weak layer of laitance that forms on the surface of the screed.

What is the cause Insufficient priming Cement and calcium sulphate cause ettringite Ettringite is weak and can cause a failure between the screed and adhesive It can also grow into the adhesive and cause it to crumble

What is the remedy? Remove tiles Remove laitance Prime with 2 coats of PR360 Tile with weber.set rapid SPF

Cracked tiles on wood Over boarding floors If the floor can be tiled with 1 bag of adhesive then either 9mm plywood and weber.set rapid SPF is suitable or 15mm plywood and weber.set rapid plus. For all other circumstances 15mm WBP Plywood is an absolute minimum. Boards must be screwed at 300mm centres and it is down to the fixer to put in extra noggins to achieve this.

What does it look like? Tiles are cracked but are well stuck Cracks are in straight lines Floors have a noticable bounce

What is the cause The cracking is caused by excessive deflection in the floor. If cracking is localised, it is most likely due to an unsupported board joint

What is the remedy Floors need reinforcing Minimum 18mm WBP plywood or suitable tile backer board If still noticeable deflection another layer is needed Weber.set pro lite rapid will give extra protection. Best solution for over boarding is a construction/tile backer board. Uncoupling membranes do nothing to strengthen the floor and offer no help in this situation.

What is the remedy Alternative solution is prime with PR360 and cover with 10mm of weber.floor flex 10mm of weber.floor flex will provide the same strength as 15mm WBP Plywood.

De-bonding on plaster/plaster board walls Same issues as with an anhydrite floor

What does it look like? The adhesive will come away from the substrate and often a layer of laitance/dust will still be adhered to the adhesive. In extreme cases, when cement-based products are used direct onto plaster/plasterboard, the adhesive will become very crumbly .

What is the cause If there is a layer of dust on the back of the adhesive this is the reason for failure. If cement based adhesive is used insufficient priming can cause ettringite to form

What is the remedy/ Remove tiles, if dusty wash clean Prime background with 2 coats of PR360

Patchy grout This is almost always caused by an excess of water either in the background or in the application. Background drying times Concrete 6 weeks Screed 3 weeks Render 2 weeks Plaster 4 weeks Skimmed plaster 2 weeks With the grout it should be mixed with correct amount of water, mechanical mixing is always preferred. When washing off best practice is to use a semi dry emulsifying pad to break down excess grout on the surface of the tile and wipe off excess with a semi dry sponge. The darker the grout the worse the problem, use as little water as possible!

What does it look like Once dry, the grout will look patchy and uneven in colour. On some occasions the whole wall and floor can be quite even in colour but much lighter than expected

What is the cause There are two common causes A natural phenomenon known as efflorescence where soluble salts within in the cement are left on the surface of the grout after the grout has dried Using too much water in the grout mix or leaving pools of water on the grout surface when cleaning the tiles can increase the risk

What is the cause Efflorescence is common to all instances where cement is used and can often be seen on the mortar joints of houses and walls. Often a thin slurry of fines can be deposited on some areas of the floor but not others leaving a patchy surface.

What is the remedy One or two applications of an acidic grout cleaner will remove efflorescence. In extreme cases, it can be easier to remove 2-3mm of the grout surface using a grout rake and then replace with fresh grout taking care not to use too much water If they will not remove the grout there are grout restorers they can apply over the top, the best one being grout rescue by Universeal, this product must be treated with care as it can become stuck to the surface of the tile and they do this at their own risk. Our preferred choice is to remove the grout and re-grout.

Incorrect Adhesive Coverage Walls dry area not less than 50% Walls wet area not less than 95% Floors not less than 95% 100% is the ideal for both floors and wet areas, it is best practice for the fixer to remove a tile during the fixing process at regular intervals to ensure that he is achieving the correct coverage.

What does it look like? Tiles de-bond and/or crack and the adhesive coverage below is less than recommended. For floors and wet areas, the contact area should be 100% with no voids. For walls not subject to wetting the coverage should be at least 70%

What does it look like? By not achieving the recommended coverage, the bond to the tile is reduced. For instance, if a floor tile only has 50% of adhesive in contact with it’s back, the bond strength is only half the recommendation and much more likely to de-bond

What does it look like? In addition a floor tile that is not fully supported is more likely to crack On heated floors, air pockets between the adhesive ribs expand and contract and this can weaken the bond to the adhesive over time

What is the cause Not enough adhesive has been used The wrong notched trowel has been used The tiles have not been bedded correctly

What is the remedy Walls – Remove tiles and adhesive (replace wall boards if necessary) and re-apply adhesive ensuring a good application technique is used Floors – Remove tiles and any loose adhesive and prime with weber PR360. Overlay with weber.floor flex to cover the remaining adhesive and allow to set. Re-apply the tiles

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