Slab Complete

As of this weekend the work on my slab is 100% complete and its about time.  All totaled it took 40 yards of fill, 10 yards of concrete, several hundred feet of rebar, 32 sheets of rigid insulation, 30 “j-bolts” and some funky deck brackets.

Maine Deck Bracket Installation

My weekend started by drilling 16 holes that were 6 inches deep into the side of my slab.  My Dewalt drill running in “hammer drill” mode was sucking down one battery for every 2 holes.  Each hole was taking about 10 minutes to drill.  When all my batteries were dead I went out and bought a new 1/2 inch bit to hopefully speed things up (and it did for about 2 holes).

My dad who is a retired machinist suggested that the carbide tips could probably be sharpened with a diamond wheel mounted to a dremel.  For anyone in a similar situation, I suggest that you research this idea…I think it would greatly speed up the process.

Once my holes were drilled, I used some wedge anchors and epoxy to fasten them into the concrete.  You don’t need to use epoxy with wedge anchors but I personally thinks its a good idea and for 20 bucks its cheap insurance.

Once the epoxy was hard, the bracket bolts were snugged up.  I then clamped on the 2×8 pressure treated boards and marked the holes for the two outside brackets.  After drilling I bolted the joist in place and marked the other holes.  To transfer the holes to the second ledger board, I simply clamped them together (matching the crowns).  The two ledgers were then bolted to the brackets with 16 galvanized bolts.

Screw Up!

As I was typing this I realized that I forgot one very important step.  The copper treatment in the pressure treated wood reacts with other metals in the presence of water.  This means that as installed my deck brackets are going to slowly be eaten away by the wood that they are in contact with.  All this because I forgot to install the plastic spacers I had fabricated.  The good news is that I still have access to the nuts and can unbolt each bracket enough to slide the spacer into position.

This is a great example of why contractors work faster than DIY builders.  They typically don’t make these kinds of boneheaded mistakes that make them do work twice!  Also notice I said “typically”….i’ll leave it at that.

Insulation Fitting

Once the deck brackets are in place I needed to wiggle the foam insulation into position.  To accomplish this I had to cut out pockets where the bolts and deck bracket would interfere.  The best tool I found was a hand saw and a Dremel Multi Max equipped with a flush cut blade.  With all the pockets cut the foam fit nicely into position.

Once the insulation was in place I added the frost skirt, taped it, and backfilled the remaining walls.  I will use a can of non-expanding foam and scrap foam board to fill in my pockets.  I am using non-expanding foam because I “think” it will have a better R value and be more dense than the expanding foam.

Starting the Porch

Since the Patriots game started at 4:25PM I had a bit of extra time to get started on the porch.  I cut two boards for the front ledger and two side pieces.  I tacked nails in the four corners so I could measure the squareness of the layout.  When I was satisfied I nailed everything with the air nailer using galvanized nails (very important in AQT wood).  I also tacked in 2 corner boards to maintain the squareness of the assembly.

To complete the job I drove eight Timber Lok fasteners thru the sides into each set of ledgers.  These fasteners can hold the outside boards to the ledgers with considerable strength, they also can support large shearing loads (deck full of people).

Next Steps

A truckload of framing lumber is scheduled to arrive this week and I will begin framing if I can get a number of consecutive sunny days.

Rainy Weekend

Sorry for taking so long to post, things have been busy.  This past weekend it rained on and off which limited what I was able to accomplish. One long dry spell I was able to install the skirt insulation around the slab.  The remainder of the time I worked on getting a bill of materials together so I could visit local lumber yards for lumber quotes.

Slab Skirt Insulation

The slab has 4 inches of foam insulation attached to the sides.  To fully meet code and protect the slab from frost I need to install insulation horizontally for 2 feet around the slab.  I used 2 inch foam and a 3/4 inch foam which provides an R factor of 14. The foam is sloped away from the house to encourage water to flow away from the slab. All the seams are taped with sticky back window sealer.  I used Owens Corning Foamular 250 which is extruded XPS foam which maintains 100% of its R value even in moist underground environments.

This insulation helps to insulate the 50 degree subsoil from freezing outside temperatures.  a 24 inch skirt around the slab keeps frost about 12-18 inches from the slab depending on the temperature.  It also works by keeping the ground around the slab dry this eliminates any chance of frost being created.

Porch Attachment

An issue that I had not fully solved until late last week was the attachment of the porch to the house.  As you can see from earlier posts I embedded “J-bolts” in the face of the slab that the porch ledger would attach to. This solution makes it super hard to properly insulate the slab in the area of the porch.

Some Google research brought me to a product called a Maine Deck Bracket.  This bracket makes it possible to attach the ledger and place 4 inches of foam insulation behind the bracket!  A fantastic idea, and at $25 each a pretty cheap solution to a difficult problem.  I’ll post pics of my install.

Tiny House “Stuff” Reshuffling

Now that I am in the tiny house full-time I’m becoming sensitive to clutter and things that are not serving a useful purpose.  I took this rainy weekend to complete some projects that will help make the space more efficient.

Slide out Table: I was using a folding TV tray as a table but it was a pain to fold and unfold.  So I installed a slide out table similar to a keyboard drawer on a computer desk.

Radio Shelf: I installed a small shelf that holds my radio and other stuff.  This frees up the space around the wood stove which will soon be seeing some action.

Clutter removal: I would not have guessed that I could have things to junk but I do.  Throw pillows for the couch…gone! why do I have two shower carpets…gone?  This box of papers that I really should keep but will most likely never use…barn.  Small refrigerator that I don’t use…barn.  Cleaning products, windex cleans most everything the rest can go.

Mice!

The mice have found their way into my tiny house and I want them gone!  I drilled holes in the flooring under the sink and filled it with expanding foam.  During my cleanup I found the hole where they were coming in and filled it and everything around it with foam.  With all the holes plugged I put out the live trap and caught a mouse within 10 minutes.  With him/her relocated, I have not heard a peep from the mice. I am also putting all food in mouse proof containers…no food = no mice!

Lumber Quotes

I got back two quotes for lumber.  The cheaper quote was about $7500 which was a little on the high side.  I decided to replace the plywood for 7/16 OSB which brought it down some.  The unexpected cost was MA sales tax of 6.25% which added nearly $500 to the bill.  I will be visiting the lumberyard this Sat to approve and pay for the order.  I will have it delivered next week sometime.

This Weekend

I will be attaching my deck brackets and moving 20 yards of fill to complete the slab.  If time permits, I will begin laying out the sill plates in preparation for framing.  If things go really well, I want to install the framing for the porch floor.  Its going to be a busy weekend!

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.

 

Rain!

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.

Stupidity!

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!

 

Inspections

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.

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.

 

Sonatubes

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.

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.
Plumbing

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

Full Gallery

Frost protetected slab detail work

This weekend work took me to the inside of my slab where I installed insulation and fill in preparation for the cement truck.

Work began with me attaching the outside foam to the forms to prevent them from moving around too much in the cement.  Screws or nails will simply pull thru the foam so I needed to improvise a way to securely attach the double foam sheets.  I used a nail and some fence wire to create a “T”.  Then I drilled a 1/8 inch hole thru the foam and forms.  After threading my “T” fastener thru the 1/8 hole I pulled the wire tight and wound it around a screw driven into the form.


The edges of my slab need to be 12 inches wide per IRC.  To meet the frost code I also need at least 16 inches buried below the ground and 8 inches above.  That makes my slab 24 inches thick which happens to be the dimension of the XPS foam I am using.

The center part of the slab will be 4.5 inches thick so that makes the “channels” on all four sides will be 19.5 inches tall.  I took a standard sheet of XPS foam and cut off 4.5 inches for the pieces used inside.

At one point I Was going to use 4 inches of foam for these inner pieces but after some napkin calculations I realized that the difference in heat loss was going to be 4% more with 2 inches versus 4 inches.  Frankly, that just was not worth the $140 to me.

I obtained a 16 foot long 2×6 that I will be using as a concrete screed and to help me set the inner forms at 4.5 inches.  Next I cut some 12 inch wood blocks to help me set the spacing between the outer and inner foam walls.  I also drove in some 3 foot long lengths of rebar to act as a brace for the inner insulation.  With all this in place I set the inner foam sheets and braced the bottoms by packing in gravel.

Next the hard work begain….filling the center.  I quickly learned that my little BX25 did not have the reach I thought it had.  I was barely able to get the fill over the inner form and I ended up moving an awful lot of dirt by hand.

Let me tell you a wheelbarrow of bank run gravel is so heavy that it’s almost too heavy to move.  After a lot of hours of sweating I finally had the center mostly full.  During the fill I had to install a lot more 12 inch braces to make sure that the foam would not collapse.

The center is very well compacted, but I stayed away from the edges to prevent them from bowing and/or collapsing.  I will do a pass around the edge with a small tamper to make the edges really solid.

 


I need to dig out some trenches for drain pipes and get the plumbers to stop by and do their thing.  View the gallery for all the weekend pics.

Completed Slab Forms

This weekend I completed the forms for the slab.  The forms are made from 2×6 lumber that I will recycle back into the house.  I will be pouring cement against the foam insulation so the lumber will not get very dirty.  The gallery at the bottom of this post has the pics from this weekend.

Form Base

I created the base of my forms by nailing a 2×4 to a 2×6 to create an “L” shaped footing.  Every 2 feet there is a place for an upright and a hole drilled for a 1/2 inch piece of rebar.  A 2 foot length of rebar is driven into the ground to help keep the bottom from moving.  The upright will be used to support the rest of the form.

Also notice that I have installed a nail in each corner to measure for squareness.  I used a clothes pin style clamp to hold one end.  I typically work alone and since my dog has not yet learned to hold one end of my tape I need to use the clamp.

After squaring the base to within 1/16″ I drove in my rebar stakes checking the squareness after each stake.

Form Uprights

I cut a bunch of 21 inch tall uprights out of 2×4 for upright members.  I sized these members short to keep them away from the top lip of the slab.  To get started I nailed these pieces in place on the footer board with an air nailer.

Top Rail

With the uprights in place I began attaching the critical top plate which will set the top of the slab.  This piece must be 100% level and straight or your slab will not come out good.

I use squeeze clamps to hold one end of each plank as I attach it.  I had the laser set up and I would line up each plank to hit a 1/2 inch mark I had made on each. As I went along I verified each plank with 4ft level and the water level.

I used 3 inch screws to attach the top plank so I can adjust it should I find something wrong.  At this point I believe that my top is within 1/4 inch of being correct, possibly better.

Bracing

I installed corner and mid bracing on the outside of the slab although I have not yet nailed it down yet.

The first thing I do is install a 2ft 2×3 stake in a spot where there are no rocks.  I use a landscape bar to “drill” a pilot hole and then drive in the 2×3 stake.  I used the chop saw to make the ends of the stake pointed.

With the stakes in, I cut to fit a 2×3 piece to brace the bottom of the form.  Then I cut the diagonal pieces and lay them in place.  The diagonal piece has the corners chopped off to make them fit better.

The final step will be to nail in the braces and double-check the top rails.  The top rails can bow in or out so you need to run a string from each corner and correct any curves using the bracing.

Insulation

The last step is to cut and tape the 4 inch foam pieces that will make up the insulation for the slab.  I am using the insulation to create the form.  The wood on the outside just supports the foam so that it does not collapse from the weight of the concrete.