You are absolutely correct, Generally the excavation is the difficult & expensive part of your repair, but you seem to have that under control. Now as we discuss the plumbing part of the job allow me to give you the correct trade nomenclature so you will be on the same page with your plumbing suppliers and inspector. Technically speaking, what you are working on is not a drain line, it is the "House Sewer" line. Code requires a main cleanout within 3ft of the point where the house sewer enters the structure. In the case of slab construction it would be found outside and approximately 3' from the foundation. For houses with a basement the main cleanout is generally just inside the footer wall and for houses with a crawlspace it can be inside or outside the footer wall. The line from the main cleanout to the septic tank or municipal main is defined as the house sewer while the main line inside the house is defined as the "House Main Drain". This is important to know because the codes allow different materials for each type of line. The raw cut end of a pipe that has no threads or fittings is called a "Spigot end" or simply a "Spigot" The formed female end of your pipe is called an "End Bell" and pipe which has an end bell on one end and a spigot end on the other end is called "Hub & Spigot" pipe so that glazed clay pipe that you have is "Vitrified clay hub & spigot pipe". It was generally made in 4' sections and when laid, the hub is always placed on the upstream end. While it can be done, as a general rule it is nearly impossible to cut that type of pipe without breaking it. (I have made & attached an illustration to help you understand the text.) To begin your project excavate until you find the end bell on a section of pipe downstream from where you want to install your cleanout. Fernco makes a rubber donute gasket that will fit inside the hub of that clay pipe, then your PVC will be inserted into the center of the Fernco. (make sure the Fernco you buy is listed as "Vitrified clay x PVC") If you can not find the correct Fernco some jurisdictions will allow you to pack the joint with "Oakum" which is a fiberous rope looking material that is impregnated with tar. To install the oakum you wrap it around the pipe and push it into the joint with a broad screwdriver, packing as tight as you can. You can make your cleanout with a Wye & 1/8th bend (sanitary 45deg elbow) in the manner you describe, but what you are making is a running cleanout and in some jurisdictions they require a running cleanout to be installed to the line can be snaked in both directions. The preferred fitting is a "Rodding Tee" sometimes called a "Cleanout Tee". An ordinary sanitary tee has a radius towards the downstream direction of flow, but a Rodding Tee has a radius in both directions. In some jurisdictions if they require a bi-directional cleanout and if you use the Wye & 1/8th bend method you actually have to make two cleanouts, one in each direction. Also not that the one for snaking in the upstream direction must be installed on the downstream side of the downstream cleanout. That is to insure that you can snake the complete line. If they were reversed you could not snake the space between the two cleanouts. You then continue your new PVC pipe to the Spigot end of the vitrified clay pipe on the upstream side of your repair and connect the PVC to the clay pipe with a Fernco coupling. (Careful here. Although both the clay pipe & the PVC are 4", that is the ID of the pipes, but because the clay pipe wall is much thicker than the PVC pipe a common 4" Fernco won't fit. Make sure you get a Fernco coupling that is listed as 4"PVC x 4" Vitrified Clay. (Although I have on occassion found them in Home Depot & Lowes as a rule you will probably have to go to a real Plumbing supply house to find the correct Fernco's) Now to answer your next question, how to cut the PVC. You can easily cut PVC with a hacksaw, a PVC saw or what I prefer for cutting 3" and larger, a common hand wood saw. Here is a tip when cutting pipe with a saw. After you start your cut, when you are about 1/4 of the way through the pipe, rotate the pipe a 1/4 turn, cut down another 1/4, then rotate the pipe again and finish your cut. Rotating the pipe in that manner will help keep a straight cut line on the end of your pipe. Sand is the preferred material for bedding the pipe and continue covering with sand until you have a minimum of 4" on top of the pipe, then you may use "Clean fill dirt" that is free of rocks until you have 12" above the pipe. When you finish backfilling it is best to have the top about 3" or 4" above grade to allow for settling. One a side note, the first clay pipe you found was 4" clay tile that was just laid end to end with no seals around the pipe, then it was covered with pea gravel. Back in the days before perforated poly or PVC they used that method to make leach fields or to install storm drains. The little gaps between the sections allowed the water in the pipe to leach into the soil the same way that modern perf pipe does.

There is no way my husband and I can remove all the capstones here--it's a very large space and neither of us have any experience with masonry. We also have, unfortunately, an immense amount of home improvement projects and very little time for these kinds of things. The mason who did this install would very likely have no interest in coming out and fixing it. When I told him we had a lot of cracking and mortar loss he said it's normal and to be expected. I'll try both of these caulks since I have multiple areas I can redo and see which ends up working better for our application. I'll post back with questions if I have them and photos of the finished job. Thanks again very much to you both.

I'm very sorry this has happened to you with your shower. I can sympathize. The shower in my old house started leaking a small amount and we had to replace it. A warning: once we started tearing out the old shower, we found significant water damage from what was probably years of minor leaking that rotted framing and subfloor. There was a lot of structural repair work necessary. I have done a fair amount of DIY including a tub/shower combo and the shower to replace the leaking one. As mentioned by @Stonetech the www.johnbridge.com site can be helpful for DIY learning. John Bridge also published a book Tile Your World. I found it and a few other published books to be helpful. When it came time to replace my leaking shower, I loved the idea of curbless shower but the correct way to build one was not something I wanted to take on. I decided to use the suggested Schluter Kerdi shower system because it solves some of the most challenging parts of building a properly waterproofed shower (pre-sloped pan, water proof drain, water proofing system, niches, etc). I cannot say who is and who is not capable of building a DIY shower properly. But I will say that the two that I've done were a ton of work, including hard physical labor, and required meticulous planning and execution. The last thing you want is to spend a substantial amount of money and time on a DIY shower that ends up leaking. There is definitely a reason why a good pro isn't cheap and why for most, they are well worth the money.

We have wood look tile on most of the main floor. We put it in 18 years ago and I still love the look. The larger stone look white tiles with light grout, I don't like as much because the grout has been a pain to keep clean. Slate look tile also ages well due to dark grout. Pros of tile are that it is hardy, easy to deal with dogs and clean ups. Hard to damage. Cons are hard to replace if damaged, grout is annoying and cracks at the expansion points between room pours of the gypcrete. And it is hard on your feet. If you get tile make sure they have a expansion line at the doorways that has flexible caulk and not grout. For grout get the premixed kind that doesn't require sealing. Better yet get epoxy. We found the premixed kind cracks less. The problem with tile that spans across pour areas or from one room to the next that is on a different heating loop is that it expands and contracts at different rates, thus cracking the tile and grout at doorways. We have had two rounds of carpet. The first included radiant floor rated rubber pad and low pile berber carpet. This was perfect and transmitted the heat well. When we replaced it we got the current version of the radiant floor rated rubber pad and a thicker plush carpet. The plusher carpet does not transmit the heat as well. The same manufacturer rubber pad (just their current model) stunk for 5 years of rubber. It was really bad at first and got better with each year but was just noxious. We had the manufacturer rep out and of course he couldn't smell it. For years we aired out the house at every opportunity and kept those bedroom doors closed 100% of the time unless we had all the windows open. It was strange because the first version of this same pad had no odor at all. We also have tarket fiberfloor in a bathroom. It is soft and easy to lay but it is easily damaged so good for low use areas. If I could go back in time I would have used a sheet linoleum like I had in my old house. It was a solid surface (color all the way through) sheet flooring and not the printed picture under a piece of thin plastic type. It may have been commercial grade but I'm not sure. I got it as a remenant and the installer loved it so much he stole the left overs to use in his own house. We didn't put it in because we didn't think it would be high end enough looking. But after dealing with cracked tiles, grout cracks, grout coming up and stinky carpet pad for years I would have loved to have gotten what was practical and let the next owners worry about looking posh.