Home Improvement--General/Bathroom Remodelling


I have a 4 part question regarding the fit of our shower room:

1 - we have lathe and plaster walls and they have been stripped and lined with ply. I believe it's marine play but I have some doubts ... how can I tell the difference between marine ply and normal ply?

2 - the room is not completely square and I noticed when the room was lined it remained off-square. I discussed this withe fitter and was told it was no problem as it would be squared off with the tile work and building up with adhesive ... is this ok?

3 - in order to make corners square I noticed that in one particular area the tiles had to be built up by 10mm or more with adhesive (could get my finger behind tile easily) ... is this acceptable?

4 - when tiling, should the walls be completely covered with adhesive (ie, there should be no voids or pockets behind tiles), and if there are a few might it cause problems?

Hello, Anthony.

I will try to answer each of your questions individually.

1.  I do not have any professional experience with marine plywood. You might locate a boat manufacturer to see if they can help you determine whether or not the boards are marine plywood. Before answering your question, I did an online search for information about marine plywood, but really couldn't find anything that might help you.

2.  If I had a similar situation with a client, I'd verify how out of square the walls are, and would talk with the contractor about the possibility of furring out the walls, not relying on built-up mortar or thinset.

3.  You shouldn't be able to get your fingers behind the tile.

4.  In 30 years of experience, I've never seen tile installed without complete coverage of mastic or thinset. It isn't a solid mass, but the tile setter uses a trowel that has teeth that relate to the size of the tile.

Sometimes, as the need arises, tile setters have to apply more adhesive to the back of tiles before setting them, i.e., if decorative tile is thinner than the field tile (called "back buttering"). The adhesive should be applied evenly, without any noticeable gaps. If there are large gaps in the adhesive, it could cause problems.

If you have any reservations about the quality of work, have an open discussion with the person in charge. I hope you get the results you're expecting, and hope that everything will give you years of satisfaction. Good luck!


Diane Plesset, CMKBD, NCIDQ, C.A.P.S.
D.P. Design

Home Improvement--General

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Diane Plesset


I will answer questions about anything to do with bathroom remodeling: design considerations, safety, function, materials (cabinets, countertops, plumbing fixtures and fittings, lighting/switching, heating and ventilation, tile, stone, concrete, tub and shower enclosures, flooring, etc.), saving water, trends, ROI, and appearance.


25+ years as a bath-kitchen design specialist, hundreds of completed bathroom projects (all styles, all investment ranges). Author of "THE Survival Guide: Home Remodeling," co-host of a home improvement program on a local radio station for over three years. Currently hosting "Today's Home" on Lifestyle WebRadio every Sunday afternoon (http://www.todays-home.com).

NKBA (National Kitchen and Bath Association), NAHB (National Association of Home Builders), PRO (Portland Remodelers' Organization), IDPC (Interior Design Protection Council).

"THE Survival Guide: Home Remodeling" (my book, published in 2003), Designers' Illustrated Magazine, Gentry Magazine, Kitchen-Bath Business Magazine, Kitchen-Bath Design News Magazine,Interior Coordinator Magazine (Japan); San Jose Mercury News, San Mateo Times, San Francisco Chronicle, Statesman Journal, Portland Tribune, Oregonian.

Multiple degrees: Bathroom Design, Residential Interior Design, Kitchen Design, and Lighting Design. Regularly attend classes and seminars to maintain current knowledge about codes, trends, sustainability, new products, etc.

Awards and Honors
Awards: Henry Adams Designer of the Year, CoTY, Master Design, Best of the Best, Chrysalis, Excellence (best home in its category), and NABE (best how-to book, 2003). "THE Survival Guide: Home Remodeling" received #1 listing in the City of Chicago publication, "Hiring The Pros".

Past/Present Clients
To see photos of completed projects, visit my website: http://www.dp-design.com/portfolio

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