Hobbit Home Progress.

Dave Lotte wrote:Noticed that the concrete guys had knocked over the light in my window.  
5 hours after the pour, i opened up the front door ( did not want to walk in the back way  ), and was hit with a blast of HOT air.

Did not know that concrete has an exothermic reaction - meaning it creates heat as it cures.

I do now !  At one point - it was 99 % humidity up too 91 F.

Was going to leave it closed in for a few days, to let the floor cure "properly", but since there are varying opinions on how long to leave it for, I have to decide to either let it sit and cure a bit or have mold start growing in my new house.

Going to open the windows and ventilate after the minimum 24 hours.

I knew that concrete setting is exothermic. But we usually have to add heat to help draw out the water. My dad likes to pour in October so that we aren't working in the summer heat.

I'm curious what the benefits of keeping that moisture inside would be? Is it supposed to keep the concrete from cracking? People pour outside all the time, and if the mix was good it often won't crack for years.

Jeremy VanGelder wrote:

Dave Lotte wrote:Noticed that the concrete guys had knocked over the light in my window.  
5 hours after the pour, i opened up the front door ( did not want to walk in the back way  ), and was hit with a blast of HOT air.

Did not know that concrete has an exothermic reaction - meaning it creates heat as it cures.

I do now !  At one point - it was 99 % humidity up too 91 F.

Was going to leave it closed in for a few days, to let the floor cure "properly", but since there are varying opinions on how long to leave it for, I have to decide to either let it sit and cure a bit or have mold start growing in my new house.

Going to open the windows and ventilate after the minimum 24 hours.

I knew that concrete setting is exothermic. But we usually have to add heat to help draw out the water. My dad likes to pour in October so that we aren't working in the summer heat.

Concrete setting is definitely exothermic!  In my own example, pouring a large volume at a hot time of year, after allowing the concrete to firm up for a few hours I irrigated the curing slab with a garden hose several times a day for the next couple of days in order to cool it and slow the cure.  The faster concrete sets, the more likely it is to crack.

Same logic applies to lime- or clay-based plasters.  They aren't exothermic as they set - lime plasters might be slightly exothermic, not sure; but in any case not noticeably so.  Still, wetting them down over days in order to slow the set will minimize cracking.

I understand they run cooling waters through pipes in dam pours to cool large deep sections.  My her was building forms for the building of Grand Coolly Dam.

For all the number crunchers out there...

14 cubic meters of concrete in the floor.
Roughly 5 X that much in walls and footings.
So, 6 X 14 cubic meters.

Here goes :

6 x 14 = 84 CM
1 cubic meter weights around 5,000 pounds ( 84 CM = 420,000 pounds of concrete walls, floors and footings )
1 cubic meters take around 2,000 BTU to raise 1 degree C. ( 84 x 2,000 = 168,000 to raise 1 degree C  ( 1.8 F ))

So to raise the house temp by 10 C .... ?

I have put in a call to the concrete guys asking to verify just how much concrete was used in the walls and footings of this house.

And so begins another stage of construction...

Needed somewhere to rest, so moved the cedar strip caned back bench in.  Then moved it away from the wall for the beginning of the wainscotted chair rail and electrical.

The Shark vaccum that i repaired out of the 50 $ box of stuff ?  Works awesome.  Reminds me to put my toys away at the end of the day.

14 hours this weekend.  Time to rest.

Matthew Nistico wrote:  The faster concrete sets, the more likely it is to crack.

wetting them down over days in order to slow the set will minimize cracking.

Totally agee,  unfortunately,  i have to consider what the high moisture is doing to the wood creating mold or mildew...
Dropping the humiditiy from 99 % is top of the list.

Floor covering is always an option in a couple of years.

Jeremy VanGelder wrote:
I'm curious what the benefits of keeping that moisture inside would be? Is it supposed to keep the concrete from cracking? People pour outside all the time, and if the mix was good it often won't crack for years.

From what i can gather,  the concrete splits the bonds of the water in a chemical reaction, so more water creats a stronger  concrete - more stuff to react with.

And that is the limit of my chemistry 😁

Gotta dry the wood out to prevent mold is my main goal.

Kind of glad i put the 1 inch pink on top of the footings in the main house.

R5  underneath, R5 on top for a total of R10.

Not a huge amount, but still makes a difference.

Will have to watch this during heating season.

Edit :  looking at thes second picture, looks like i get a 4 degree temp difference when compared to the outside footing

Dave Lotte wrote:

Matthew Nistico wrote:The faster concrete sets, the more likely it is to crack.

wetting them down over days in order to slow the set will minimize cracking.

Totally agree,  unfortunately,  i have to consider what the high moisture is doing to the wood creating mold or mildew...
Dropping the humidity from 99 % is top of the list.

Floor covering is always an option in a couple of years.

I assume that your Plan A is to stain and seal the concrete slab as a finished floor?  That is my plan for my own slab floor... which also has some significant cracks where my concrete finishers did a shit job in a couple places.  Oh well, I'll just have to deal with it.

If you end up covering your slab, you'd of course want to use ceramic tile or something similar.  No wood or foam or carpet.  Nothing to isolate your living space from the thermal mass of your slab.  Particularly in your case, since that thermal mass is also your design heat source via your hydronic system.

But you know all this already.

Matthew Nistico wrote:

If you end up covering your slab, you'd of course want to use ceramic tile...

Have not gotten this far yet, but i am not discounting any options.

Variables :

1.  Super efficient house.  Can install any type of floor - water temps will be slightly hotter with a  nicer look.

2.  Safety.  Walking around on the concrete,  trip and fall - thats a hard landing.  Composite flooring will cushion that a bit.

3.  Breakage.  Drop a glass mug, pot or plate.  With the floors as is - guaranteed it's smashed.  Composite will lessen breakage.

4.  Sore feet.  Working in my bare feet right now, and after 5 hours my feet are killing me.  Going to have to change that !

Have not looked into this as of yet.  But will find something to cover the variables.  
Comfort and living in the home comes first.

Just curious
Have you contemplated and earthen floor with linseed or similar sealing?

Rico Loma wrote:Just curious
Have you contemplated and earthen floor with linseed or similar sealing?

No.  Through all stages of construction, there is one thing i HAVE to keep in mind.

Building inspector approval.

By using well known procedures - i have avoided any number of delays and setbacks.

1 week after the concrete pour, and it's starting to cool down a bit....

Humidity is still up there, but not as high as it was.

14 hours in on this unexpected long holiday weekend.

Wooden beams had to come down - they were in the way.
Left wall ✔
Back wall ✔
Back porch - 80 % ✔
Right side - 50 % ✔
Front walls are not done.

Nothing is lagged down yet, as i have to laser level the entire thing shimming it level as i go.  Concrete guys tell me the footings were within 1/8 of an inch of level.  Going to do better.

Used up all my top planks, so time for a rest.

So much for that idea ....

My straight micro clover roof has died a horrible screaming death.

Time to test plant some different, more hardy plants.

Dave Lotte wrote:So much for that idea ....

My straight micro clover roof has died a horrible screaming death.

Time to test plant some different, more hardy plants.

Suggestion: don't pick one of these new options.  Spread seed for several at once.  It is possible the most hardy will eventually take over.  If so, then you've saved yourself the time of multiple, serial experiments.  Or it is possible that two or more might achieve equilibrium and then you'd have a polyculture roof instead of a monoculture.  If so, then for visual appeal if nothing else, it would be an improvement.

Dave Lotte wrote:My straight micro clover roof has died a horrible screaming death.

Too hot or too dry or both?

You were planting into disturbed soil, and from what I've been hearing, Ontario has had crappier than usual weather this summer.

At the very least, with luck, the clover roots are supporting the soil while you try something else. You likely started with few microbes or bugs.

Good luck with round two.

I have not been following every day, but normally with concrete you dont start framing on it until it is dry.
An exterior slab in daylight may be a week or so at least, maybe longer.\Did you allow a good amount of time for drying?

Another hot and humid one today.

Here are the thermometer readings for those interested.

First,  outside, in the shade.
Second, inside old house above bed.
Third,  temperature "station".
Fourth,  hobbit home.

Accurate to within a few degrees of each other.
Concrete floor is still drying out in the hobbit home.

John C Daley wrote: with concrete you dont start framing on it until it is dry.

Yes, and no.

Now that the floor is poured,  I will be watching the humidity levels in the home.
With an estimated 2 years for the floor to completely dry out,  the framing is getting done either way.
With an estimated 700 gallons of water in the floor alone, it will take a while to completely dry out.

Asked the building inspector if i could use fresh cut lumber from the Amish saw mill, and he said "no".  Turns out, kiln dried lumber is more dimensionally stable when its humid.
Less twisting and warping.

Will be posting updates as i go.  Right now, i plug in the dehumidifier and the temperature goes up.  With 100 + temps outside - trying to avoid that.  Once the cooler weather gets here, i can leave it running and really dry things out.

Dave Lotte wrote:
Yes, and no.

Now that the floor is poured,  I will be watching the humidity levels in the home.
With an estimated 2 years for the floor to completely dry out,  the framing is getting done either way.
With an estimated 700 gallons of water in the floor alone, it will take a while to completely dry out.

Asked the building inspector if i could use fresh cut lumber from the Amish saw mill, and he said "no".  Turns out, kiln dried lumber is more dimensionally stable when its humid.
Less twisting and warping.

Yes and no. Depends on whether the person selecting the lumber understands grain twist. I've seen plenty of kiln dried, graded lumber end up twisted and warped. If buying Amish, you should be able to ask the miller directly and get a trustworthy answer...

Coydon Wallham wrote: If buying Amish ...

No.
The one major objective of this project is to keep the building inspector happy.  He says "no" - i don't argue.

I can frame in my walls with local materials.  

This always impresses me.

Finished off the chair rail ( half wall ) in the main room,  and both sides of the little end pieces for the front door measured exactly 7.5 inches.  Concrete guys know their stuff when the front door opening is EXACTLY centered.

Front and back doors trimed out, now to finish off the back porch and get started on the main walls !

I can hear the model trains running already 😂

People ask .... why are you building this

Mentioned Thermal Mass a few times on here.

Time to add part 2 - Thermal Lag.

Scenario:

House is sitting at 60 F - would like to heat it up to work in.
Start up the 80,000 BTU heater and run it for a solid hour.
House goes up to 70 F, and i work for 5 or 6 hours, nice and comfy.

Go out the next day, and it is back down to 60 F.  What the heck

We already know that if i have 55 cubic meters of concrete in the walls and floors,  that it would take around 110,000 BTU  to raise the inside temperature 2 degrees Fahrenheit ( 1 C ).

Thermal lag is the time it takes for the mass to soak up the heat.  So when i turn off the heater - the room temp comes back down to match the temp of the concrete.

Explains why it takes 3 days for the temperature to change inside.

Cool.  Once i move in and set the thermostats - it will be temperature stable for DAYS.