Porcelin Tile Installed Without Grout

I have a deck installed over my porch and it is a flat roof. I had the whole deck replaced last year and the contractor did an inferior job. I am having to replace the tile portion of the deck and I am nervous becuase my new contractor is saying he can install the procelin tiles without grout; just butting the tiles together and he says it would be a better seal. I told hin I was worried that the tiles would crack due to being outside and on the second story over the porch. He says this will not happen, but I am nervous. I have never seen tile installed without at least 1/8" grout. I have already wasted $4,000. 00 and just this part of the deck is costing another $2,500.00. It is not that big an area and I don't know if I should let him go ahead with this.

Your quick response would be appreciated. Thanks.

I am not one of the experts on this forum, but I do get a lot of good information from it for my projects. I am certain when they respond to you they will tell you to stop your contractor and do not give him any more money! Tile cannot be laid without grout, and just butting tiles together is asking for big trouble.

Is the tile being used even suitable for outside? I personally think you are being taken. I would suggest not doing anything else until you hear from the pros here!

STOP, DO NOT LET HIM do anything. Yet. This is an outdoor deck. Will it be waterproofed? If there is no grout, the answer is immediately no. Will the deck be subjected to freeze/thaw? If so, a porcelain tile is required. Will the deck have a slight grade for drainage?
Tile inherently is not perfectly square. Hence the need for grout lines to allow for these imperfections. By butting tiles together, there is no room to play with. What is his reasoning for going groutless?

He thinks it would prevent leaks. I have never seen indoor or outdoor tile installed without proper grount.

I forgot to mention that the contractor put AC Granual Ice and Storm Seal (Self Adhesive Underlayment) and taped all the overlaped areas with a special tape. I had questioned the change from our agreement of rubber EPDM and he claimed this does as good a job. I sure hope so.

You are being taken by someone who is not qualified to do what you need. Probably the best product for your use is Noble Deck. Post back how the roof deck was constructed; joist span, spacing and size, decking type (assuming plywood, was it pressure treated, etc. How about where you live, are there snow loads to consider?

Stop all work now before it gets way to expensively wrong.

"AC Granual ice and storm seal" is used for sloped roofs as a ice dam water protector. I am sure its better than no membrane but it will not perform anywhere near the rubber epdm that was spec'd. It also costs about 1/10th as much if you are wondering why he used it