I have been asked to quote for commercial premesis where the grout on the shower tiles has become black with mould.

My initial thought is to remove the old grout with a fein, treat the grove with a mould killer solution, re-grout and then seal.

The cleaners have been scrubbing at the grout in an effort to clean and this has resulted in the grout being partly removed and so the grove between the tile is certainly deep enough to take new grout without removing the old.

Could I therefore use a mould treatment and simply re-grout?

What would you charge pre linear metre for this?

Any thoughts would be greatly appreciated.

hi SUB50,my advice would be to use a mould and water repellent grout such as MAPEI Ultracolour plus.I would also charge your day rate x whatever you think it will take...hope this hepls m8....Bri

Thanks for the reply

Would you remove the grout first?

Take it you would use a fein, or similar if you were?

Daywork for me.

Yes i would use a Fein m8 to get some more grout out.

[quote=sub50;115747]I have been asked to quote for commercial premesis where the grout on the shower tiles has become black with mould.

My initial thought is to remove the old grout with a fein, treat the grove with a mould killer solution, re-grout and then seal.

The cleaners have been scrubbing at the grout in an effort to clean and this has resulted in the grout being partly removed and so the grove between the tile is certainly deep enough to take new grout without removing the old.

Could I therefore use a mould treatment and simply re-grout?

What would you charge pre linear metre for this?

You can do what you have suggested but the black mould will probably reoccur. There is a misconception that black mould starts on the surface of the grout and this in the main is not true. The spores grow under the grout so generally the mould is usually attached to the back of the grout and consequently to the substrate.

Provided the tiles are ceramic or porcelain and therefore not acid sensitive I would approach the problem as follows:

1. I would rake all the grout out.
2. I would treat all the grout with phosphoric acid.
3. Rinse thoroughly.
4. Then clean all the grout lines and tiles with Heavy Duty Tile & Grout cleaner.
5. Check all tiles are secure and fix where necessary.
6. Treat the grout lines with anti mould.
7. Regrout using a good quality grout with microban usually Mapei or BAL.

Then as a final step I would paint all the grout with Aqua Mix Grout Colourant which is an epoxy colourant and will ensure the grout remains totally waterproof in the future.

Kev

[quote=TilingLogistics;115770]

Originally Posted by sub50

I have been asked to quote for commercial premesis where the grout on the shower tiles has become black with mould.

My initial thought is to remove the old grout with a fein, treat the grove with a mould killer solution, re-grout and then seal.

The cleaners have been scrubbing at the grout in an effort to clean and this has resulted in the grout being partly removed and so the grove between the tile is certainly deep enough to take new grout without removing the old.

Could I therefore use a mould treatment and simply re-grout?

What would you charge pre linear metre for this?

You can do what you have suggested but the black mould will probably reoccur. There is a misconception that black mould starts on the surface of the grout and this in the main is not true. The spores grow under the grout so generally the mould is usually attached to the back of the grout and consequently to the substrate.

Provided the tiles are ceramic or porcelain and therefore not acid sensitive I would approach the problem as follows:

1. I would rake all the grout out.
2. I would treat all the grout with phosphoric acid.
3. Rinse thoroughly.
4. Then clean all the grout lines and tiles with Heavy Duty Tile & Grout cleaner.
5. Check all tiles are secure and fix where necessary.
6. Treat the grout lines with anti mould.
7. Regrout using a good quality grout with microban usually Mapei or BAL.

Then as a final step I would paint all the grout with Aqua Mix Grout Colourant which is an epoxy colourant and will ensure the grout remains totally waterproof in the future.

Kev

Hi Kev,

what is this Aqua mix grout colourant exactley.?

cheers
Gary.

It's a treatment for colouring the grout, It usually has two coats applied. A mate of mine used it and was impressed

will be stocking Aqua Mix grout colourant in a range of colours very soon

plus most the rest of the Aqua Mix range too