Random Thoughts Post Slab Pour

Its been a couple of days since I poured my slab and I thought it would be good to share some observations that might save others trouble with their own builds.

Concrete trucks are really heavy

No I mean really heavy.  The driveway that I drive on all the time with my small pickup truck is hard packed and my truck tires leave little if any impressions.  The concrete truck left 3 inch deep ruts in a couple of places!  Additionally, when the truck delivers material the driver needs to drive forward and back to deliver it to the correct spot.  Make sure your ground is solid.  The driver makes you sign a paper saying you are responsible if he gets stuck.

Rakes and Hoe’s Suck

Moving concrete around in the forms can be done with a normal garden rake but a concrete rake is much better.  Unfortunately, it’s a specialized one use tool but worth the extra money IMO.

Some people may also consider a bull float a necessity.  If you are looking for a shiny smooth slab then it probably is.  In my application where there will be a sub-floor over the cement, I think the skreet I used would have provided a suitable (but rougher) finish.  Since my brother in-law had access to a bull float I used it but it was not needed.

Bagels make lousy feed for your helpers

I bought a bunch of nice bagels and OJ and no one ate them.  My brother in-law arrived an hour late with a dozen donuts and everyone devoured them.  Lesson: Donuts not bagels!

Attaching foam to your slab

You will want to attach the foam boards to the slab with some type of mechanical fastener.  Had I used 2 inch thick foam there are commonly available concrete fasteners at the local home store.  I am using 4 inches of foam and there’s nothing available so I had to improvise.

Building codes now require AQT compatible fasteners for deck construction.  Timberlok makes all sorts of fasteners to fill that need.  There are also a number of generic options at the local home store.  I found some green 5 inch epoxy coated lag screws with a star drive head.  These fasteners are not rated for use in concrete, however in this application they do not need to hold very much load.  You just need to hold the foam against the concrete.  I paired these fasteners with some galvanized roof tin washers to do this job.

You need a 6 inch long 5/32 masonry bit and a hammer drill to make this work.  First you drill a hole thru the foam boards into the concrete.  Using an impact driver, you drive the fastener into the drilled hole being careful not to drive too deep and strip out the hole you drilled.  You may find that applying a 5 minute epoxy to the threads will produce a stronger bond to the concrete (I did not use it however).  I did this on a 3 day old slab which may have helped just a bit with the concrete being softer.  I would also say that an impact driver is needed to complete this job.  With a depleted battery I was not able to drive the fastener in all the way, but a fresh battery worked fine.

The Bodega has a new slab

It was a beautiful fall weekend in New England this weekend.  Perfect weather to go out for a hike or stay home and pour 11 yards of concrete.

When it comes to pouring concrete its a real good idea to have some extra bodies to lend a hand.  I several family members come over to help out with this job.  The next door neighbor also needed a small slab poured so he helped me out and bought the remaining concrete that was left on the truck after my pour.

The pour went really well, during the pour the only mishap was some of the vapor barrier making noise as some of the rebar poked thru it.  I also had a small amount of bowing on the sides which I will need to deal with during framing (not a huge deal).

the wooden holders I made for the J bolts worked as expected, but left impressions in the concrete that I will need to seal when I put down the sills.

The slab was poured at 9AM and was hard enough to walk on by about 5PM.  We pulled a couple of the boards off to see how it looked and it looked like a large concrete block.  I decided to leave the forms on overnight because the cement was pretty soft still.  I took the opportunity to shave off any ridges using a brick like a sanding block.  I wet the top of the slab and put a tarp on it to help slow the curing which makes it stronger.

The next day (Sunday) I created a nice pile of wood to recycle and some nice camp fire wood as I removed all the forms.  The two forms in the center for the well tank and shower were pretty difficult to remove since I overbuilt them.

The next task in this project is to attach the foam insulation to the concrete in a more permanent manner.  I will then lay down 2 feet of foam 3 inches thick on all sides to keep frost from getting under the slab.  I’ll have pics…

Bodega Slab Ready To Pour

Well almost ready.  The building inspector still needs to look at it.  Provided there are no unforseen issues I will be calling in a concrete truck to drop off 11 yards next Saturday.  As a treat I decided to put together a video tour of my completed slab (not my finest work, I’ll try harder next time):

Saturday Adventure

Saturday we had the plumbing inspector scheduled to come over in the afternoon and there were a couple last-minute issues to attend to.

First off, the pipes that would be run thru concrete needed to be wrapped with insulation to keep them from breaking should the slab settle.  The plumber brought over a roll of light blue sill insulation that we applied generously to all the pipes that might come into contact with concrete.  This was a bit overkill since code only requires it at the point where pipes come vertically thru the slab.

Next, we needed to prove that there were no leaks in the drain pipes.  A device that plumbers refer to as a “dildo” or more correctly named a “test ball plug” (not sure which term is worse) gets inserted into the outlet pipe at the clean out.

Using an air compressor, you blow up the plug so that no liquids can pass by.  For the first time I removed the cover from my new septic tank and made sure that no liquid was coming out of the inlet when water was poured into the drain pipes.  Basically you just make sure that the level inside the drain pipes stays at the same level for several hours.

The Inspection

The plumbing inspector stopped by mid afternoon and carefully looked over the job and declared that it passed.  I brought him the building permit to sign and we chatted about local politics for a while and he left to enjoy his weekend.  Very easy process overall.

Finishing Touches

With the plumbing inspection out-of-the-way I filled in all the missing dirt, added insulation on top, and covered the remaining 25% of the slab with vapor barrier.  Now that the top drain pipe is wrapped and covered with vapor barrier, it’s not the big problem I thought it would be.



Naturally its going to rain this week.  A completed slab with vapor barrier makes a great swimming pool so I need to keep it protected from the rain.  I attached 2 pieces of wood and strung some fencing wire to form a bit of a tent.  Hopefully I can keep most of the water out.

Underslab Plumbing

After being held up for weeks I finally have pipes installed!  The main 4 inch pipe sweeps nicely under the foundation.  This pipe is bedded in sand so that rocks won’t poke thru.  There is also a vertical pipe that rises to grade for servicing the pipe (cleanout).

Once under the slab the pipe rolls up to a very funky PVC tee which has an extra 2 inch port on one side.  The bottom of this fitting connects to the septic system.  The main 3 inch port (would be the tee port if this were a standard tee) connects to the toilet.  The other 2 inch side port connects to the shower drain.  The shower drain has a trap installed under the slab.

The top port is bushed down to 3 inches and runs over to the wall.  The kitchen sink, vanity, and washer drains will go here.  The stack vent will also connect to this pipe.


You notice that the top pipe is very close to the top of the slab.  In fact near the wall its only 1 inch below the surface.  The radius of the elbow is going to make it tough to install the sill boards for the wall.  Why on earth did the plumber do it this way?

He wanted to reduce the pipe size to 3 inches at the cleanout and run 3 inch lines in the slab.  This would have lowered all the pipes by about 4-5 inches and put them just below the level of the concrete.  The plumbing inspector is a ball buster and *might* have given him a hard time about that setup.  Not wanting to cut the job apart, he did it the way he thought the inspector wanted to see it and not the best way for this job.  The stupidity in this state is amazing!



Tomorrow the plumbing inspector will sign off in the afternoon.  I will finish up the slab work and get the building inspector to approve the slab and hopefully next weekend the slab can be poured.

PV Panel Surge Supression & Updates

As you may have read in the news we got hit with some pretty nasty weather here in the Northeast this weekend.  I watched a wall of water head my way as I worked on things Saturday morning.

I ordered a surge suppressor from Midnight Solar a few weeks back and has yet to install it.  I opened the panel for my electrical system and connected the red and black wires to a pair of unused terminals.  I then connected the green wire to my ground stake.  As expected the blue lights inside the device lit up to tell me it was working.

The storm passed without incident however I soon discovered that the surge suppressor is very power hungry!  My Xantrex system monitor went from -0.1 amp to -0.4 amps.  The fan on my composting toilet draws about .1 amp under normal conditions.  The additional .2-.3 amps was going to feed the lights and leakage currents thru the surge suppressor.

Needless to say its unacceptable to waste this much power so I disconnected the device and will reconnect it when there is a change of lightning.  I’m thinking that there may be a way to install a diode module between the charge controller and panel that will prevent using power from the batteries.  I don’t mind wasting a bit of PV power but a constant draw on the batteries is something I can’t live with.

Another option may be to tame the power consumption by removing the blue lights.


Plumber Update

As expected the plumber called me yesterday afternoon to say he would not be coming.  The next work day will be Thursday.  I wanted to pour concrete this weekend…I guess that’s not going to happen.  Thing that pisses me off is that I could install these drain pipes in 2 hours.

More Slab Detail Work

This weekend was very quiet compared to weekends past.  I have been very stuck trying to get a plumber to do my slab work.  This Saturday I finally found a reasonably priced plumber that says he will start Monday (today).  I did manage to work on some details between rain showers.



The porch of the Bodega sits atop three concrete piers.  To install them I dug three holes 48 inches deep and filled the bottom with about 6-8 inches of hand mixed concrete.  Before the concrete hardened, I stuck 4ft pieces of 1/2 inch rebar to keep the piers shear strength.

When installing piers you normally need to be concerned with three dimensions (left, right, and elevation).  Since I poured footings, I did not need to worry about elevation when setting the tubes.  I simply aligned the tubes to the side of the slab and the correct distance from the slab.  When in the correct location I backfilled each tube and compacted the soil.  With the tubes securely in place, I can use a board and level to mark where the tubes need to be cut.


New Tool

I bought a new laser level a couple of weekends ago.  It’s the GPL3T made by Bosch and it cost me about $100.  It made installing the sonatubes much easier than using a piece of string and measuring 3-4-5.  I simply aligned the base of the level with the side of the slab and “presto” I had a dot on a place near where the tube should be set.  It’s a well constructed laser and it’s already made my life easier….$100 well spent!

“J” Bolts

Every slab needs “J” bolts installed to fasten the walls to the slab.  The IRC says you need to have the body of the bolt inserted 7 inches into concrete.  You must also install bolts 12 inches or less from board ends and every 6 feet.  My sills will be 3 inches thick, so I need to use 12 inch “J” bolts.

Personally I feel that “J” bolts provide a great deal of strength to your structure in wind loads and I want to do better than what the code requires.  Since I have my house in CAD, I drew up a sketch to locate the “J” bolts in every stud bay which comes out to about 24 inches give or take.

One problem you have is getting the “J” bolts in the right location, depth, and plum.  To ensure that this job is idiot proof I built some wood brackets that will be screwed onto the forms once the concrete is poured.  These brackets will set the bolt in the perfect location (if all goes according to plan).

This Week

I’m off to babysit the plumber who hopefully shows up.  I should be able to complete the slab details this week so I can call the cement truck for a Saturday pour.  Keeping my fingers crossed.

Off-Grid Tiny House Living Update

I thought today would be a good day to offer some insights about my off grid living situation.  It’s now going on two months living in my 66 square foot house and I have had a bit of time to learn some new things.  In no particular order:


My 150 watts of PV panels and batteries have worked out well.  Generally speaking I have been using about 10 amp hours from my 200 amp hour battery bank each night.  It has been very important to have switches to turn things on and off as needed.  Weekends I seem to use a bit more power and weekdays a bit less.  DSL and computer is my largest consumer of electricity.  I try to keep my laptop and mobile devices charged in the car and at work to help reduce the load on my system.

My feeling is that a 3-4 day stretch of cloudy days is the limit of my little PV system.  I have not had the need to use my generator for battery charging but I do think I may need to at some point depending on weather.

A future modification I’m going to look at is adding spring-loaded mechanical timers to some of my switch plates.  My DSL modem would be a nice item to switch off automatically, especially at night.

I also have a slot on my PV rack for a 50 watt panel.  At some point I will fill that open slot to enhance my electricity production for the winter months.


My decision to use a cooler rather than an electric refrigerator has been a good one.  I’m paying about $4-7 per week for ice and I always have nice cold drinks.  As winter gets going I expect this to drop to zero.  I should get into a routine of freezing ice at work instead of buying it…on my to do list.


I am attempting to keep a low profile and limit the use of my cabins LED lights.  I have been using my Nokero and d.light solar LED lights quite a bit.  They really work well and help reduce the power draw from my PV system.


Its been getting colder and the forest rodents think my little house will make a nice nest for the winter.  I bought some foam in a can and a live mouse trap.  I see no reason to kill mice as they are just doing what mice do…I just want them to do it someplace other than my cabin!

The can of foam filled in the gaps where mice could enter and the trap caught 2 little mice that I relocated to the wood pile.  The trap is still out and has not caught any more so my foam job seems to be working.

Cabin Modifications

I made a few comfort modifications in the past couple weeks:

Loft bed – I removed the 4 inch foam mattress and replaced it with an air mattress.  It’s a good upgrade but the air mattress makes a lot of noise rubbing on the floor.  Comfortable sleeping is a challenge in my tiny home.

Couch – I added a support that allows me to slide out the seat without it tipping forward.  I also added a filler piece to insert behind the seat.  This modification gives me a second place to sleep.  In the winter months, I will probably sleep downstairs when the wood stove is fired up.  Unfortunately, there is not enough padding on the couch to sleep comfortably…a future project.

Dog Bed – My dog and I do not share the tiny floor space very well so I bought him a small bed and put it on the floor under the wood stove.  He has learned to go there to stay out-of-the-way.

Future Modifications

I use a TV tray for eating and it just takes up too much room.  I am thinking about installing a slide out table from under the wood stove to make better use of my limited space.

General Impressions

Living in a tiny off grid space is really not that big of a deal.  I have all the comforts of home with very little sacrifice for a lot less money than a big house.  Things are working out very well.

With winter coming up I will have the challenge of keeping things from freezing and staying warm with my Shipmate tiny wood stove.  It should be very interesting…

Holiday Update

I have not posted in a while and I have many things to talk about.  The detail work on my slab is close to being complete and I am getting things ready for the concrete truck.

In the state of MA, residents are just too stupid to glue pipes together.  It’s possible that someone might be overcome by the smell of PVC glue and become injured somehow….its for the children…keep them safe!

Someone somewhere (probably a plumbers union) decided that only licensed professional plumbers are allowed to install pipes.  This has led to a situation where plumbers just don’t give a shit.  They cherry pick the jobs they want to do without returning phone calls for the other jobs offered them.  Many quote extreme prices for small jobs hoping to gouge the shit out of unsuspecting consumers.

One plumber quoted me $7500 not including fixtures to plumb my little bodega.  At first, I thought “maybe this is going to cost more than I thought”.  Then I looked at his quote and he had listed “ABS drain pipe and fittings” at $675 just for the materials!

Being curious, I pulled out a tape and determined that it would require about 11 feet of 4 inch pipe, and 9 feet of smaller 1.5 to 3 inch pipe to complete the job.  The job would require about 10 fittings.  Quoting $675 for 20 feet of pipe and 10 fittings can only mean a few things: 1) this guy is a crook, 2) he wants to see if i’m an idiot, 3) he did the quote wrong, 4) he really does not want the job.

I need to keep looking….so far 3 phone calls/emails and no responses.

Insulation, Vapor barrier, and Rebar

In my last post I had the center part of my slab filled in with gravel.  This weekend I compacted that gravel and brought the level to within 2 inches of the top.  I then installed 2×8 foot sheets of insulation over the top.

The vapor barrier is a product called Tu Tuff.  It’s a 4 mil plastic sheeting that reminds me of potato chip bag material.  The vapor barrier is laid over the foam and tucked into all the nooks of the slab to hopefully keep moisture out of the slab.

On top of the vapor barrier I installed rebar (which is pretty expensive BTW).  Code requires me to have two 1/2 inch pieces at the bottom of the footings and one at the outside edge near the top of the slab.  I also added some cross pieces to make the slab even stronger.  Before the pour I will install some mesh over the top of the rebar just because.

You will notice that 1/4 of the slab is undone….thats where all the plumbing needs to go.

Deck/Porch Details

The front porch will be about six feet deep and will sit on concrete piers in front and be bolted to the slab.  Its much easier to install “J bolts” than drill fasteners so I laid out the bolt pattern on the foam insulation and stuck the bolts in place.

My concrete piers I just dug three holes 4 feet deep and used 6 bags of concrete and some rocks to pour footings.  The building code requires 13 x 13 inch footings 6 inches thick.  Mine are probably thicker and wider as I just filled in the bottom of the hole.  Note that I also installed some 1/2 inch rebar to prevent the frost from shearing off the piers (happens a lot here).

Plumbing Layout

The last thing I did in preparation for the plumber was to install mock walls so the plumber could figure out the exact locations for everything.  The shower pipe will have a 12×12 box around it to allow the plumber to install the trap post concrete pour (rebar stake in box).  The large box is the form that will create the recess for the well expansion tank

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