Saturday, December 24, 2011

Stemwalls and Rat Slabs - Part II


So, helping me get the stem-walls completed and working the concrete during the pour, again, is Joe Strickland from Skyline Development and his crew, Bob and Nick.

In come the pump truck and the concrete truck:

The pour started with the front corner and slowly progressed around the house. The major issue with pouring concrete walls is the pressure that builds up at the corners. It's entirely a matter of hydraulic pressure and the corners will face the greatest loads. So the guys were incredibly careful when pouring the corners.

Here you can see a good view of the concrete pump filling the cavity in the ICF. There is both horizontal and vertical rebar within the cavity.

Once the stemwall pour was complete, we quickly finished preparing the crawlspace for the rat slab. The dirt had already been graded and the next step was to lay down a 6mil plastic barrier that would help limit moisture migration into and out of the slab.


While the guys were handling the rat slab, I started setting the various bolts. There were two types of bolts, hold downs, which needed to be set in a specific way so that they looped around the rebar in the stem-wall, and anchor bolts, which only needed to be set in the concrete, but without any special placement. Here you can see the guys finishing up the rat slab and you can see the anchor bolts set into the stemwall.

And the result is incredible. I now have a smooth rat slab, a strong stem-wall and I can begin working on the next phase of the project (rough framing).

Stemwalls and Rat Slabs - Part I

As you'll note, it's been over a month since the last post. I (naively) thought that the stem wall would go rather quickly. And, realistically this *could* have been the case.

But I had a few decisions to make, and once the decisions were made, I had to finish up the work to make it happen.

The big decision was around interior of the crawlspace, and whether I should insulate the floor of the crawlspace now and cover it with a thin layer of concrete. (This thin layer of concrete is called a "rat slab" because it's not thick enough to be structural, it's just thick enough to keep rodents from tunneling up through it.)

The advantage of pouring the rat slab at the same time as the stemwall, is that I wouldn't have to have the pump truck come out a second time, and the pump truck costs roughly $600 per visit. The disadvantage is that I haven't picked out the type of insulation I want to use to insulate the floor. Normally, when insulating a floor like this, you place the insulation underneath the concrete (see above).

In the end, I decided I would go ahead and pour a rat slab when I pour the stemwall, but I wouldn't insulate underneath. The reason I think this will work is that I'll simply place the foam insulation above the rat slab and then lay down a plywood subfloor above to protect the foam.

Normally, this wouldn't work very well, but because the crawlspace will not be heavily used, the plywood should do a decent enough job of distributing the load.

Now that I've made the decision to pour the rat slab, I also had to figure out how I would support the house during the pour. Currently the house is supported on the interior with eight steel posts sitting on 1/4" steel plate. Unfortunately these supports are on the interior where the rat slab needs to be poured.

So I consulted with my architect and confirmed that I could support the beams with some of the left-over 2" pin pile pipes. I then used a laser level to cut the various pipes to the perfect length to bring the house to level.

Above, you can see the pipes after they were cut and welded to 1/4 plates on the bottom to help distribute the load. I also took the precaution of filling the pipes with concrete so they wouldn't be hollow, on the assumption that this would help strengthen the pipes.

I then jacked up the house a little bit, positioned the pipes underneath the beams and welded the pipes to the beams. I then welded the pipes to the vertical rebar, so that they would be supported laterally and keep the house from moving. And as you can see in the picture below, the posts were positioned within the stem-wall.

So I used a relatively "cheap" rotating laser when performing the measurements. According to the laser, the footings were sloped by about an inch over the length of the house. That didn't seem extreme to me, but when Joe the contractor came out, he was surprised. He was very exacting when he leveled the footings, and used his *very* expensive and *very* accurate laser. As soon as he said this, my shoulders slumped because I realised my laser was likely off and I had cut the pipes to the wrong lengths.

This led to him using his really awesome laser to help me figure out how far off each of the beams was from level. I then had to figure out how much I would need to shim each beam in order to bring the beams and house to perfectly level. This took about two hours, but I can't complain too much, because now the house should be level within 1/8". And because the foundation is sitting on pin piles, there will be virtually no settling. It is a little surreal to think that 50 years from now, this house will still be level within 1/4".

Now comes the ICF! ICF stands for Insulated Concrete Forms. The idea is that you used thick Styrofoam for the forms, and then after you fill the forms with concrete and the concrete cures, you leave the forms in place. The Styrofoam then acts as insulation. An added bonus is that they are pretty quick to setup as well!

The easiest way to think of ICF, is as large, hollow LEGO blocks. You stack them up and overlap the edges for strength.

Up next, the concrete trucks show up again and it'll be time for mud!

Tuesday, November 29, 2011

Trees be gone

From the footing pour, you might remember that the trees out front were a pain in the ass.

Well, no more!

I had an arborist come and remove the trees. Because the trees were on a city owned planting strip, I had to have the work approved by the city arborist and then utilize a city approved contractor. But luckily, due to the time of year and the slow economy, it was relatively cheap.

I had them leave the firewood, which I'll give to my neighbors.

Tuesday, November 8, 2011

Time for MUD!

(Mud is slang for concrete.)
When I last left off, I had decided to bring in a contractor to get the foundation completed and get the house framed up. Well I sought out bids from roughly 10 contractors and in the end, ended up going with one who had previously worked with a friend on his renovation. I chose Joe Strickland with Skyline Development. Great guy, intelligent, respects my budget and has tons of ideas for making the whole build faster and more efficient.

Onto the foundation!

The first thing to be done was to setup the forms and tie the rebar for the footing. This wasn't trivial as it would require a little excavation cleanup and then leveling the forms, reinforcing them and finally getting the rebar cut and in place. Joe and his son Bob, did a terrific job.

The inside form is made from 2x8s and the outside is a plastic drain / form called Form-A-Drain. The idea is that it will be used as a forms and then left in place as the perimeter drains, instead of having to install a 4" perforated pipe. I chose it because it seemed like it would make the footing easier to form and also because I had limited space for excavation and it would help with that. In the end, it was a pain in the ass to work with, and I'm not sure I would do it again.
To place the concrete, a pump truck was hired. The truck had a boom that would raise over the house, so that it could place the concrete around the entire perimeter without a lot of hassle. I couldn't believe how much easier this made the job, it was terrific.

In total, 12 yards of concrete were ordered, split into two trucks, one truck had 8 yards, the second truck had 4 yards. This is the second truck arriving.
 The process is simple actually, the concrete truck backs up to the pump truck and unloads the concrete into the hopper.

This picture hopefully shows the scale of the trucks, they are both quite large. Also, I was happy with the amount of use the curb cut took. I'm happy to say it fared perfectly well, no cracks, no damage.

Here, you can see the boom as it reaches over the house and pumps the concrete into the form at the back of the house. You can also see Joe and Bob working the concrete into the forms and smoothing it out.
You can tell from Joe's smile that this is the completion of the pour. I estimated that we would need 11.6 yards of concrete and so I ordered 12 yards, just in case. It turns out we needed just that amount. It worked out perfectly, no waste.
One of the odd things I found during the demolution, was that someone had placed a horseshoe under one of the original concrete piers for the house. I assume it was placed there for good luck. I made sure to save it.

So now, with the new foundation poured; I placed the old original horseshoe into the footing, along with the handprints of those who will make this house a home.

Tuesday, November 1, 2011

My first theft....

So I met a plumber at the site this morning to discuss the side sewer connection. It was early and I was a little out of it.

But after a while, I realised that something looked "off". I looked around and realised that someone had been to the house and stolen the old cast-iron waste pipe and the left over pin pile pipes. (Edit: the pipe was left, I was merely oblivious to it.)

All told, this was the first theft at the house, for which I'm grateful. And they only stole the leftover material. They left the rebar alone, and they left the foundation forming material alone, but still.


Friday, October 21, 2011

Starting the foundation

So this last weekend, I intended to get the foundation footing forms setup and ready to go. Good idea, but I don't think I understand how much time I will need to spend getting the forms setup, the rebar cut and in place and I certainly don't think I can do the concrete pour by myself.

So I did the next best thing, I stayed busy by prepping the rebar, getting it cut and bent.

So now that the rebar is ready, I think I am going to call around and find out how much a foundation contractor would charge me to come in, setup the forms and install the foundation. The concrete work seems really daunting to me, mostly becuse I really need the foundation to be square and level, and it's concrete, so you only get one chance to do it. If I mess up, it'll be too costly.

Sunday, October 16, 2011

Pile Driving Completed!

It's been a while since my last post. Well, yes. The reason is that I managed to injure my back on the last day of pile driving. I only already finished 8 piles that day with only 7 left to go, and I was excited. At that point I was running the pile-driver on the interior piles in the house, and without much overhead clearance I was lifting the driver onto the pipes by hand (ie, no chain winch to assist me). And of course I arched my back picking it up and I could feel the muscle tear as it happened.


Now, as I said, I'm pretty burly, so I put on a back support and finished out the day in pretty wicked pain. But goddamnit, I wanted the piles finished, I didn't want it dragging out any longer. Plus, my month of pile-driver rental was almost up. So I persevered and completed the task.

Then I proceeded to do nothing for the next three weeks but sit around on muscle relaxers and hang out with my new best friend. Which brings me to the next picture!

This is Bubba. Bubba and I have lots in common. We like long walks in the park, jumping up on people, licking faces and peeing on things. You could say it's a match made in heaven. This day Bubba was hanging out while I measured how how much of the pipes to cut off.

To explain what I'm doing above....

This is the detail from the blueprints showing how the foundation will tie into the pin piles. You can see that once the piles are driven, you install a cap on top. This cap is then embedded into the foundation footing. So my next step is to use a rotating laser level, and then cut off the pipes so that they are all level and roughly 4" above the bottom of the concrete footing.

Here, I've already measured the pipes and cut them off. Now I need to clean up the excavation so that all of the pipes are 4" above the ground, and then install the caps.

Here the excavation is cleaned up and I'm ready to install the caps.

Remember how I said the caps were $20 dollars if I purchased them? Well, I can't stand to buy what I can easily build, so I fabricated them. I spent about 7 hours fabricating them, with material costs of roughly $5 per cap. So 48 caps * $15 per cap means I saved roughly $720 doing this myself. It also means I paid myself roughly $100 an hour to do this. That's roughly 4x times the wage I would get as commercial welder.

And the end result, the excavation is cleaned up, the caps are installed on the piles and I'm ready to begin setting up the forms for the foundation!

Saturday, September 17, 2011

Pile Driving - It's what happens when a man and a house love each other

So, where did I leave off? Ah, that's right, Pile Driving!

As mentioned before, this house was built on top of old, unstable fill. And there is an old stream below this area, which means there is the potential for peat. During the purchase, I had a geo-tech bore test holes and from that determined that there was no peat to be found (good!), but the soil was fairly unstable in the upper layers. This means that I would need to either use a *LARGE* shallow footing foundation, a slab foundation, or pile piles with a grade beam.

With either the shallow footing or the slab, I would need to excavate to soil that would compact and in my case, I knew that wasn't likely. So that would mean over-excavating and then bringing in fill and compacting it. That sounded like a massive and unknown pain in the ass, so I chose to go with pin piles. This would have the potential to be more expensive, but it would also mean a fixed installation schedule and I wouldn't have to worry about the underlying soil, I could just dig and be done with it.

And bonus, if you use 2" pin piles in Seattle, testing is not required, so the homeowner can install them! And you all know how much I like doing this kind of stuff. So again, here is a picture of my pipe that I'll be using. It's 2" schedule 80 galvanized pipe. I didn't have to use galvanized, but it will last *a lot* longer than black and it wasn't that much more expensive, so, what the hell. All told I ended up buying 80 10ft lengths. Unloading these was a pain in the ass as they each weighed about 50lbs.

I bought the pipe from a pile driving contractor who also sells the supplies for "self-installs". So when I placed the order, I also ordered couplers and caps. When I picked up the order, I realised that I could easily fabricate the couplers and caps and save a shit ton of cash.
Specifically, they wanted $25 per coupler. A coupler was just a piece of schedule 80 1.5" and schedule 80 2" pipe welded together.
I realised the material cost for each coupler was less then $5, and the same thing for the caps (which were slightly less at $20 per unit). And to put this into perspective, I would need at least 48 couplers and more likely 60+ and 48 caps.
So I could earn about $2k in sweat equity fabricating them myself. And bonus, I like to weld!

Here is an example of the couplers I made.
Here, you can see the piles I've started on the outside of the house. In total, I would be driving 40 piles from the exterior and another 8 from the interior of the home.

When I started, I rented a 90lb jackhammer from Aurora Rents with a special pile driving bit. In total the hammer with bit weighed somewhere over 110lbs or so. So imagine balancing a jackhammer on top of a pipe, 10ft off the ground and trying to keep it all going straight, while not falling off a ladder.

In addition, the goddamn pipe would mushroom in the tip and I would need to beat the pipe with a sledge to get it out of the tip before I could drive the next pipe segment.


Suffice to say, I don't have any pictures of these escapades, but it was foolhardy at best, and *REALLY* f'n slow. It took me roughly 8 hours to install the first 2 piles. Admittedly I was slightly defeated, until I picked myself up and started calling around questions and I found something that made me believe in man / machine love.

THIS IS IT! The tool of my dreams. It is a 140lb pile driver. It's entire job is to sit on a pipe and beat it into the ground, without me needing to balance it.

I could only find one for rent in King County, and I ended up renting it for an entire month for $900 and it was worth every penny. EVERY PENNY.

This tool saved my sanity and gave me hope.

Remember how I told you it was 140lbs? Well it's almost entirely cast iron, and it's a bitch to lift. Even as burly as I am, I knew I couldn't keep lifting it all of the time, especially when I am running 10ft segments of pipe. So I fabricated a tall stand with a chain winch. This allowed me to easily lift the pile-driver to the top of the pipe without killing myself.
Remember how I said the homeowner can handle the install of 2" piles? Well the catch is that the city requires someone to inspect the pile installation and ensure that they are driven to the geo-tech's refusal criteria. This means I had the privilege of paying a guy to watch me install the piles and make sure that they moved less than 1" in 1 minute for 3 consecutive minutes.

And now, a video of the pile driver in action!


Tuesday, August 2, 2011

Meet the new workhorse

A friend had an old truck he didn't really need anymore and wanted a place to park it. I told him he could park it in front of my house. He asked if I wanted it, I thought about it and said sure. So the agreement is that I'll use it and maintain it. If I sell it after I'm done, we split the profits.

The only caveat is that I had to paint the truck olive drab green. Ostensibly I was also supposed to add a sickle and hammer, but I deferred that for now. My house is enough of an eyesore, I'd rather not add to it by insulting my neighbor's political sensibilities.

But I did paint it, with a roller and paint provided by a previous owner. It came out pretty well actually. It looks kinda shitty close up, but from 20ft it looks great!

Monday, July 4, 2011

More Excavation - A little bit off the back

 So here is where the excavation left off. It was, for all intents and purposes, complete. But then, before I started driving the pin piles, I realised that the house was now *VERY* small inside, with a 720 sq ft footprint, with an odd dimension of 20x34. I realised that it would be better to extend the house back to the full 40 ft. This would give me more efficient use of material and would also provide an additional 120 sq ft of floor space.
 So, looks like I get to rent the excavator again! And you know how heartbreaking that is. Oh and you can also see in this picture the 2" schedule 80 galvanized pipe which will be used in the next phase of construction.

And here is the end result, another six feet off the back of the house has been excavated. The dirt has been piled up in the back yard and will be used to back fill once the foundation has been poured.

In this picture, you can also see the Insulated Concrete Forms, which will be used for the stem walls.

Thursday, June 30, 2011

Perimeter Excavation

Now that the interior has been excavated and leveled, it's time to start the exterior excavation! This is the first picture showing just how much work needs to be done.
After a bit of excavation, you can see it's starting to look pretty good.
This is the old cast-iron side sewer connection. This thing was a bear to remove.
The south side of the house was filled with larger rocks, so I added rebar probes to help dig out the larger rocks. Now it looks pretty gnarly.
Here is the north side of the home as it neared completion.
Here, you can see the south side of the house nearing completion.
And the end result, the excavation is complete! I like this picture, it makes the house look like it's floating.