My lifelong dream of having a heated clay mud pit in my backyard is finally a reality! I've used UMD for years but never saw anyone build a system like this. Now that it's done I want to give back and share details of how I built it so if anyone in future comes along they can benefit. Here was an earlier conversation on UMD I had for my own inspiration: https://umd.net/forums/heated-mud-pit

Thanks again everyone in that thread and this site!

My requirements were that any mud pit needed to be large enough for me to lay in fully, heated somehow, clay mud, be completely discreet from the neighbors, need to run off 15amp extension cord & garden hose, and offer a showering/cleanup area (using hot water) to get 95% clean before heading inside.

FYI: I intended to do this as cheap as possible so labor was by myself (plus Mrs. MudLust) and it was made to be removable if needed so that's why below I didn't use a permanent structure.

The Design

Below are the layers of the mud pit itself I ended up with so you all can understand easier, starting with the mud and working down:

Clay mud (red art clay & bentonite)
Large tarp
Electric heating wire (taped to the insulation)
2in thick foam insulation
Another tarp
Soil underneath

The Build

The core of everything is the greenhouse enclosure. I found the largest one on Amazon which was 12x8ft. It has translucent white panels that allowed some light in. That was just large enough for about a 9x7ft mud pit plus a shower area. Mine is secured with large U rebar stakes hammered around all legs so wind will never move it.

Next I started digging, lots of digging. I aimed for a 7ft wide x 8ft long x 3ft deep mud pit. I ended up a little shallower due to the insulation but overall it was a good size for me. I used a square shovel to move the clay/loamy soil. The spot I needed to use had some rocks and tree roots so I definitely needed the mattock (pickaxe). I also used a cordless reciprocating saw to cut larger roots up. It took like half a week of work over the course of a month or so (fitting it in with life) to get it dug completely. Invested in a wheelbarrow which helped me get rid of the digging dirt around the yard. It was full of rocks and other bits so not what I wanted to use in the pit itself.

Next was laying a base tarp down, followed by the 2in foam insulation boards. These were 4x8 sheets that I cut up to completely line the sides and bottom of the pit. The foam I used had a foil lining on one side, so I put that face up. I want to reflect the heat up into the mud pit. I taped the pieces together and secured the sides from falling inward. Cannot overstate how important using some insulation is for keeping the heat inside the mud pit.

Next was running the heating cable. First time I ever used this but it's intended purpose was to heat bathrooms and be mortared under tile and such. I chose this product because it can be powered fully by 15 amps (120v) which I can get via an extension cord to the mud pit. I was initially intending to use a hot water system to circulate hot water from a water heater but I found this suntouch product and went with that. I prefer to make this setup as simple as possible, even if electric heating is not as energy efficient over hydronic based systems. Anyway I laid it out in a grid onto the foil insulation board, taping it down as I went. You cannot cut the wire as the system is designed to be used completely as is. So I measured the pit dimensions and reviewed the product to find a decent length roll (400ft) for adequate coverage.

Next I got this huge tarp to completely cover everything. This tarp will prevent the wire from being disturbed over time and offer another layer of protection from accidental damage. I cut some 2x4's up to make a lip for the front edge of the mud pit so that shower water drains away outside. The tarped covered the mud pit and the shower area in a single sheet. This was important so nothing could leak out or could come up between. I secured the tarp with the same U rebar stakes.

Next I worked on the shower area to the front of the greenhouse. I wanted a self sufficient clean up area with hot water so I could use the mud pit in cooler weather more comfortably. The shower head is zip tied to the top of the greenhouse support. To that I connected the water heater. I used a 8 gallon point of use/ RV water heater since that was a 15 amp (120v) unit plus it was small enough to fit under the shower on a little platform made of 2x4 and plywood. I had used the Pex A system before and had some leftover pipe that I used to connect everything together. It's fortunate I do plumbing work as I have leftover pieces to cut costs. I used various plumbing fittings also, supplyhouse.com was great to find some of the more niche fittings. When using the mud pit I just run my garden hose over to the greenhouse and connect to the inlet which is at the base. Yes the proper way would be to trench and run a pipe and tie it in properly but this was a proof of concept for me so it isn't made to last forever. Especially when we move in the not too distant future, I'll need to disassemble everything.

Finally was the moment that I've been looking forward to. Filling the mud pit with clay! Per the recommendations of this community, I found a pottery store close enough to me. I was able to have delivered to my home all the dry clay I would need. I ended up using a mix of cedar heights redart clay and bentonite clay. I originally was just going to use the redart clay because it was the cheapest option but I found the finished mud pit was too dense even after watering and mixing thoroughly. I discovered the bentonite mixed in helped me slip in easier and made the mud pit less dense overall. This was important because I want to be able to fully envelope myself in mud. I ended up using 96 of the 50lb bags of dry clay total. Just did the math, that's 4800lbs lolol, the clay store never asked why I needed that much clay, they happily took my money. Mrs. MudLust laughed at the pallets of clay being delivered.

Next was mixing the clay. I ended up just emptying half the bags into the pit to start. Added water and gave it a preliminary mix then added the rest. I did everything by hand so it was quite the workout but I'm an early 30's guy so not too bad. It took 2-3 days to get this step complete. I used a N95 mask and goggles because the clay dust was a hazard when dry. It completely clogged my mask and would irritate my eyes so glad I used the PPE.

Heating

After letting the mud hydrate and mixing over the course of a week, I was ready to try heating it. The SunTouch warmwire heating system allowed different thermostats to be paired with their systems. I chose a relatively smart unit which I wired up with some spare romex wire I had on hand. The thermostat controls the power to the mud pit heater and that connects to an extension cord I run from my house. Yes again this is not permanent and was a proof of concept so not it's not meant to last forever. The thermostat is smart so I can connect it to my phone and adjust the temperature of the mud from anywhere!

The Result

I'm absolutely thrilled at how it came out. It was everything I could want without absolutely wrecking me financially. The heating works well, it takes a couple days to heat up fully from cold but it can reach over 90F max. The thermostat has a probe that lays in the mud to get the current temperature. I lay 2 sheets of foam on top of the mud to reflect heat back and keep the warmth inside when not in use. Once heated up it holds the temp pretty good, if it's too thick then it overheats. It feels undescribable, smooth silky mud that warms and cradles you at the same time. It feels great to make love in it and with it as there is enough density and thickness to really pleasure you. The shower with the hot water is great, I can get 5-7mins of hot water during the colder months. I expect even more during the summer. The shower head is removable so I can get the mud out from all the cracks . There is complete privacy from the neighbors who just see a greenhouse on the outside unaware of the mess within. I often just walk out in a robe and flip flops for my sessions where I can completely destroy myself and then clean up before coming inside. Even in the winter I'm able to use the mud pit which blows my mind. Overall pretty happy how it turned out.

Rough costs are broken down below all in USD:

Clay: $2,000
Mud Pit Heater: $770
Water Heater: $225
Portable Greenhouse: $200
Building Supplies: $200
Plumbing: $150
Total: over $3500

The Negatives

Being the first time I've built anything like this, there were some learnings along the way that I would do differently again. Also some limitations due to our present situation in life. For one I should have mixed the dry clays together before adding water as incorporating them later was more difficult once hydrated. The space works well enough size wise but does feel cramped for 2 people only when cleaning up as there is limited space at the front to shower. Also hot water is limited so each person needs to shower quickly to make it last but it recovers fully in less than 10 minutes. The clay needs to be watered at least once a week which isn't a big deal as to maintain the best consistency it needs water. Due to the temporary nature, I need to winter proof the water supply when we get freezing temps but that is manageable. Also the greenhouse is not built to handle any amount of snow so it requires a central support to handle the weight. It did come with a support pole and I attached it to a 2x4 running along the top of the foam covers so it's weathered a couple snow storms just fine. I only have 15 amps of power to work with at any moment so I cannot run everything at once but it works well enough. I have automation through the smart outlets to turn things on and off in sequence to avoid tripping the breaker.

Bonus Details

I also hooked up a small electric pressure washer inside the greenhouse so I can more easily get water deep into the mud pit. It's plumbed directly into the same water feed as the water heater. Works well for loosening thick mud. I also have a fan, air heater, and lights hooked up for comfort. I have all the electrical components plugged into smart outlets inside a weather proof box so I can control everything from my phone. I can even use my voice to turn things on/off when I'm covered head to toe in mud. The lighting makes it nice as it is RGB so I can set various moods. My favorite at the moment is the fire theme, which makes it feel like a campfire vibe. The fan and air heater help adjust temperature and humidity as needed.

Links

Greenhouse: https://a.co/d/03TfpBKZ
U Rebar Stakes: https://a.co/d/0hAGBpgk
Electric Mud Heater: https://a.co/d/03RdBL8h
Mud Heater Thermostat: https://a.co/d/01CYHhdf
Water Heater: https://a.co/d/092xuKUY
Shower Head: https://a.co/d/09QNFWqJ
Foam Insulation: https://www.homedepot.com/p/RMAX-Pro-Select-R-Matte-Plus-3-2-in-x-4-ft-x-8-ft-R-13-1-Foam-Insulation-Board-637898/313501510

I hope this helps others with their own mud journey. This was a labor of love that I built to scratch my own mud itch and also help Mrs. MudLust feel more comfortable and safe to play with me. Thank you to her for indulging me lol.

I'd love to have folks come visit that are interested in playing with me (Mrs. MudLust won't partake with others at the moment). I'm on the east coast USA. I'm a private person so I won't divulge details on this post but feel free to DM me. I'm open to men, women, or anything in-between. I just want to share this awesome mud pit with others, have plenty of horny mud sex, and fulfill some of my own fantasies and perhaps yours too

I have a new hero ! Well done!

Well done. Did the heating actually work?

In Florida mine had to be off the ground or there would be all kinds of bugs and snakes in it. Get a the biggest paint mixer you can find in on Amazon and stir it more.

Phil

Thanks! Heat works great, I can get it plenty hot for the winter so I suspect the summer will be even more. Just takes a while for heat to travel through the mud but its gotten over 90F if left cranked heating for multiple days.

I spray the outside of the greenhouse with bug spray occasionally as a preventative measure. Other than that I've only seen 1 or 2 bugs inside but the clay kills them quickly so not something I'm too worried about. The clay itself seems to be pretty inhospitable to most creatures except us lol.

Thank you for sharing your build. I had an indoor heated pit built with the same concept - wooden frame, foam core insulation, electric heating cable, and pond liner on top. One recommendation I would make is to consider using roof deicing cable instead of radiant cable - it's the same 5 watts per foot product as radiant heating cable, but 300 feet of cable costs only $100 - significantly cheaper than floor cable.

Another problem that you have thankfully not run into is pit depth and sliding cables. Mine is 3 feet deep, but the sidewall heating cables shifted down over the years and only the bottom 2 feet gets heated. I solved this problem by getting a second set of deicing cables and have them make direct contact with the top layer of mud, and it's plugged in to a second breaker - this cuts heating time down to a few hours.

Problem three if you want a good submersion is buoyancy... you float if more than half of you is above the mud. You will want some grips under the mud to pull yourself under if this is the case. My solution for this was getting two large hollow cinder blocks, wrapping them in soft yoga mat foam, and then sealing with vapor barrier plastic and duct tape on top. Zip tie both of them together and then sink them at the ends of your pit... now you have arm and ankle grips that let you pull down and wiggle all the way to the bottom of the pit. Or to keep you in place when someone else is on top of you.

Great ideas, especially cheaper cabling and the weights. If I ever do this again, I'd consider doing like a custom concrete encased loop with built in hand holds and what not.

Got to go shake the money tree lol

Looks like you are set up for some fun now! Thanks for the detailed post and pictures!

I played around with a very temporary heated pit last summer...kind of set up for a week or two, tear down, etc. But it was great to have for a few of the chilly nights leading into summer and early fall.

A couple of points for consideration: (I just scanned the thread so these may be mentioned somewhere else)

- If you're losing a bunch of water / drying out, be sure to keep plastic over the top, and some insulation, too. This will help keep water in and lower the heating bill.

- Electric heat is great. I found some 'auto regulating electric ice melt cable'. 120 feet for about $70. It runs about 5-8 watts per foot, so serves as a 600+ watt heater. It will regulate itself at 150F - which is way too hot for mud. A thermostat would be great for long term, but I just plugged mine in, unplugged after some time, to regulate heat.

- Obviously with anything electric and 'water' ABSOLUTELY USE a GFCI outlet to cut power in case of any broken insulation. Me, personally, I also unplugged everything before even getting close to getting in. The thermal mass of the clay was more than enough for hours+ of play.

- In some pics, it seems like you used a tarp for a liner? If that is the case, I hope yours is heavier or more durable than the one I used. My last experience with a tarp - they are actually woven strands with a plastic coating - it broke down in fairly short order and mud started leaking through the weave. Small bits of grit in the mud + footsteps on the tarp accelerated that considerably - so maybe if you have pure clay it won't be as much of an issue. If it becomes a problem, you might look into plastic sheeting in double-digit 'mils' for thickness. That is usually pretty durable stuff. High end, you might look at a 30 mil pond liner. That should last essentially forever.

Anyway, let us know how it goes!!