Bathroom project with some issues:

I removed an old bathtub from my master bath and would like to place a new Kohler tub. After speaking with a local plumber, he said I need to change my existing P-trap (that is buried in cement (condo was built ~25 yrs ago) and this requires chiseling into the concrete around and may cause damage to the apartment unit below us. He didn't give specifics as to why other than we won't find any tub that could fit to the dimensions of the current drain location.

Another plumber said there would be no problem.

So I am now asking for help, here are the details.
The current drain is a 1.5" metal drain (I think its iron?) that is attached to a p-trap buried deep into poured concrete. The center of the drain is located 2.3"-2.5" (I wasn't too exact) from the bare wall studs in front (no drywall in place yet, but we will be putting 1/2 or 3/4" cement board with Tile on top for the tub walls.) and exactly 16" from the one finished side wall.

I am looking to install the Kohler Portrait 5' tub. Info found at: http://www.us.kohler.com/onlinecatalog/pdf/1022148_4.pdf
And
KOHLER: K-1108-RA: Portrait® 5' bath: Baths: Bathroom (http://www.us.kohler.com/onlinecatalog/detail.jsp?from=thumb&frm=&module=Baths&item=8024802&prod_num=1108-RA&section=2&category=10&resultPage=0--568174913)

Is everything OK for this install or do I need to remove the P-trap? Any thing else I need to keep in mind for this install? Do we need to install anything under the tub before putting it down or can it sit directly on top of the flat concrete sub floor? Can I buy Grohe faucets and use a Kohler tub?

Thanks in advance!
Mike

Good morning Mike,

The current drain is a 1.5" metal drain (I think its iron?) that is attached to a p-trap buried deep into poured concrete. The center of the drain is located 2.3"-2.5" (I wasn't too exact) from the bare wall studs in front (no drywall in place yet, but we will be putting 1/2 or 3/4" cement board with Tile on top for the tub walls.) and exactly 16" from the one finished side wall.
Ya lucked out! Your Kohler will rough 16" off the side wall and 2 1/4"off the front plate. I don't know why plumber #1 told you that you had a problem unless he was figuring on the Kohler roughing in at 1 1/2" off the front plate and 15 1/2" off the side wall. This is a normal rough for older tubs. Good luck, Tom

Hi Mike:

Not only will you be fine with measurements as presented, but the tub waste and overflow assembly has some adjustability (left/right and back) behind the tub so that if off by say a 1/2" or so this will allow you to align and join all... see picture below.

Are you planning on installing a ledger strip on the back wall to support the back wall of tub? Also, are you planning on installing this tub in a bed of mortar or similar to reduce creaking, etc. associated with all acrylic/fiberglass units?

Let us know if need info. On this...

MARK