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Newbie questions on first timber frame build

Started by michilius, July 20, 2021, 12:52:31 PM

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michilius

All,
I'm moving to a new property in the upper midwest in a couple months and one of my first projects will be building a chicken coop that can comfortably hold 30-40 chickens.  For a while now I've hoped to get into timber framing to build out my homestead infrastructure and I see this as a great starting point.

In terms of experience, I have virtually no construction or carpentry experience (raised in the city/suburbs), so I have to research even the most basic questions.  I have, however, been doing hand tool woodworking for furniture-making for the last 5 years, so I do feel comfortable with skills like layout and joinery on a smaller scale.

I've purchased and read through Timber Frame Construction by Jack Sobon & Learn to Timber Frame by Will Beemer, so I'm starting to become familiar with some of the terms and concepts related to the craft.

Here's my current plan and some questions I'd greatly appreciate feedback on from the wealth of experience this forum represents.

Timber Frame
- 8'x10' sill footprint building with 14' plates to create some overhang on the two shorter sides
- Joinery and design style similar to the 12' by 16' cabin in Will Beemer's book (core frame timbers are 7x7s or 8x8s), with my build having only 2 bents rather than 3
- See three attachments for the drawings



 


 


 

Foundation
- Will fully support the sills 1' off the ground rather than be on pillars.  There would not be any joists or constructed floors in the timber frame since this trench created by the foundation will become a deep bedding pit that will be periodically cleaned out and used to make compost
- QUESTION: This home is near the Canadian border, I love the idea of a real stone foundation with lime cement.  Do I need to dig a foundation down below the frost line for this small of a building?  Also, it's critical that the deep bedding area stay dry otherwise it will become smelly and unhealthy for the chickens, would a lime cement and stone foundation potentially leech water into the inside?

Siding
- The home has board and batten, so I'd like to try this with real white oak boards that will be painted
- QUESTION: Is this siding structure waterproof with the wood boards alone or does it require some type of caulking or other technique to make sure water doesn't get behind the boards?  Is horizontal siding a safer bet?
 
Windows
- There will be a 3'x3' window on each of the longer sides of the building
- QUESTION: Any good sources you all would recommend for how to frame the windows and put in exterior trim with the board and batten in order to make sure this part of the structure is waterproof?

Roofing
- Will be putting a standard shingle roof

Interior
- there will be no interior finishing, just roost bars and a layer box system

Don P

Hi michilius,
Frost heave requires moisture and small soil particles. For important buildings we just place the footings below the frost line as a matter of risk management. If the soil is granular or solid rock so that moisture cannot accumulate or act on the soil then it isn't necessary to start below frost depth. If the soil is clay or fine grained it is good insurance. A little bit of lazy can cause all kinds of work later.

No foundation can exclude hydrostatic pressure so the main thing is to make sure that water cannot rise. Drain tile around the exterior with clean gravel all wrapped in landscape fabric to keep soil out of the drainage rock. The tile either exits to daylight downhill or empties into a pumped sump pit. On my current job I'm bringing that perimeter drain inside to a sump as well as and interior perimeter and subfloor drain all to a pumped sump, but that is a house. The interior floor should be above the drain tile level, preferably above exterior grade. The exterior grade should fall away in all directions from the building or at least swaled and away to keep surface water running away from the building. Build on the pitchers mound whenever possible.

This is one area where I think portland based mortar shines. I would use it to lay the stone and to parge any below grade exterior work, then foundation tar paying attention to the intersection of wall to footing. It is best to form a concave cove of mortar at that intersection to help with tarring and moving the water away. Dragging a short piece of pipe along the joint helps form the cove.

Board and batten is fast and easy but is difficult to flash well. Horizontal siding does work better  but there are plenty of examples of old B&B buildings. Good overhangs are the best detail. Planing boards and battens lets everything lay flatter and seal tighter than rough sawn. Full sheathing covered by a weather resistive barrier then the siding is "correct". In other words look at the siding as the pretty cover, the WRB as the water turn and the sheathing as the bracing and WRB backing. Single wall can work but it is a compromise. On a chicken coop a lot of this is over the top, just giving info.

GAB

Well cared for chickens worth their keep will lay 300 or more eggs per year.
35 (average of 30 to 40) x 300 / 365 = 28.76 eggs per day.
I hope you like quiche and omelets.
GAB
W-M LT40HDD34, SLR, JD 420, JD 950w/loader and Woods backhoe, V3507 Fransguard winch, Cordwood Saw, 18' flat bed trailer, and other toys.

CJ

 Welcome to the forum, Michilius. I've been here for a few years myself, but still consider myself to be a newbie as well. I took a few timber frame courses (two - one week sessions) back in 2018. One week was building a rafter structure (16'X20') similar to that of Jack Sobon's build, and the other was a truss build where we constructed a 14'X20 structure with two king trusses at either end and a hammer beam in the centre. Both courses were the best most constructive things I have ever done, and well worth the money spent too! That was the extent of my building prowess. I have made a gazebo in my backyard and some renos to the interior of my house. Other than that, I'm like you. I did buy Will Beemer's book to keep my mind fresh of everything I had learned, and it helped greatly when it came time to build my 14'X18' frame.
Anyhow, I'm with DonP on this. Spend the time to do it right and eliminate possible blowback later on down the road. I'm not sure how deep the frost gets there in the mid-west USA, but here in central Ontario in Canada, the frost permeates through the ground and can get pretty deep depending on how much traffic is compounding the issue. Make sure that you have good drainage and away from the structure. I used a Type II stone 2"- which is ideal for water drainage and topped it with 5/8" gravel.
My timber frame is a sleep cabin or a bunkie as well call it here. I poured a slab on grade foundation with 15" around the sill perimeter and 6" in the middle. However, your build will be for chickens, so you obviously won't be going that route.
I see you have girts in your drawing. One thing I've learned, and if I had to do it again, I wouldn't put them in because they take away from the size of my windows. If you want them, it's your choice. They really don't serve much of a purpose at that size. Are you insulating it? If so, I built my walls on the outside of the frame itself. That exposed all the timbers and everything.
I am going with a vertical board on my exterior, but it isn't board and batten. I was going to go that route, but I opted to go with a vertical board made by Canexel and come it 10" widths by 10' long boards. They are painted with high pressure that is impregnated into the product that will make it weather worthy for twenty years, by which time I will probably be dead. Maybe not? Anyhow, either vertical or horizontal siding will do and if you are unsure about precipitation getting in behind, then maybe think about a Typar barrier which will prevent water from getting in. I'd also go with a pine board rather than hardwood too. Pine weathers nicely. JMO
I know that this was a bit excessive, but I want you to get a good idea from my perspective as a new guy on the block, and getting any kind of insight is useful, especially by those who have experience.
So keep us posted of your progress. I will be keen on tracking your steps. Cheers!










Planeiron

Quote from: michilius on July 20, 2021, 12:52:31 PM


Siding
- The home has board and batten, so I'd like to try this with real white oak boards that will be painted
- QUESTION: Is this siding structure waterproof with the wood boards alone or does it require some type of caulking or other technique to make sure water doesn't get behind the boards?  Is horizontal siding a safer bet?


Hi michilius
Your plans look just like the one's I made from Will Beemer's book! I'm no expert but I used board and batten or in my case board on board made from Siberian Larch rough sawn. I think the most important thing is orientation of the boards relative to the growth rings taking into account the way the boards will want to cup as the rings straighten out. You can use this to your advantage and arrange so that the boards cup into each other at the overlap forming a tighter seal. My boards overlap an inch to 1 1/2" and inside is bone dry so far. Fastening the boards in a balance of enough nails/screws to hold but no so much to completely restrain any movement.
I have a large number of planks of green oak that came from the beams. I was going to use these for siding but decided against it as green oak moves so much that you might need to allow for this additional movement with oversized holes and washers (at least that is what I was told).
Good luck with your build. This will be a hen house palace.
  

scsmith42

Welcome to the FF and best of success on your project.

Excellent advice from others more experienced than I in the responses above. 

What I would like to share is that in your drawing, where your rafters intersect the top plates your design is weak. The tapered end of the rafter tail should begin below the plate, not above it.

As you have it drawn, the rafters will most likely split horizontally above the plates.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Jim_Rogers

Quote from: scsmith42 on September 16, 2021, 07:50:31 AM
Welcome to the FF and best of success on your project.

Excellent advice from others more experienced than I in the responses above.

What I would like to share is that in your drawing, where your rafters intersect the top plates your design is weak. The tapered end of the rafter tail should begin below the plate, not above it.

As you have it drawn, the rafters will most likely split horizontally above the plates.
Scott: That is a traditional step lap rafter tail and seat in the plate.
Like this:


 
If cut like this the rafter will not split.
Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

scsmith42

Quote from: Jim_Rogers on September 16, 2021, 10:40:03 AM
Quote from: scsmith42 on September 16, 2021, 07:50:31 AM
Welcome to the FF and best of success on your project.

Excellent advice from others more experienced than I in the responses above.

What I would like to share is that in your drawing, where your rafters intersect the top plates your design is weak. The tapered end of the rafter tail should begin below the plate, not above it.

As you have it drawn, the rafters will most likely split horizontally above the plates.
Scott: That is a traditional step lap rafter tail and seat in the plate.
Like this:


 
If cut like this the rafter will not split.
Jim Rogers
Jim, thx for the detail. The way the original drawing looked it appeared to me that the thin end of the rafter extended above the plate.
What you posted looks good.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Don P

I think the wording in the engineering reference is that a gradual taper approaches full strength. With the more recent versions of the code that is a non prescriptive rafter, nowhere notched more than 1/4 depth, the tail is a problem. I don't have to agree but I do gotta comply, if inspected check first.

CJ

 Here's what I did for siding on my build. It's from Canexel and it's a engineered wood product (pressed particleboard) with the paint impregnated at the factory. Fifteen years on the paint and twenty-five years on the product itself. It'll outlive me.
 Easy to install with strapping running horizontal for the walls and vertical strapping for the upper gable ends. As you can see, I ran short of siding and had to order more. All in all, I am pleased with this product.  










mattgancz

Dear Michilius:

I laughed as I read your post because I just came in from clipping hens wings.  I do not know all of the details of your life, so forgive my blanket advice, but I would highly discourage a stationary coop --- save the timber frame for something else.  I currently have a small coop that I move around by hand.  It is about 8' x 5', and contains a roof, roosts, nest boxes, and food and water.  It does not have sides.  The coop is surrounded by electric poultry netting from Premier 1, and a solar fence charger.  I move the coop one day within the fence, and the next day I move the fence up to the coop.  The chickens move around the yard cutting and fertilizing the grass, and eating bugs.  The electric fence keeps out racoon, bear, and foxes.  Weasles don't really climb, so they are not a bother either.  In the winter the chickens go in a hoop house where I put down leaves and woodchips throughout the winter.  The carbon acts like a diaper, and holds the nutrients of the chickens' manure until it can be used in the spring --- then they are back to their sideless hut.  I built my portable coop in about an hour with scraps from my sawmill.  I hatch 30 chickens in the spring, butcher the males and second year hens in the fall, and winter over a new batch of hens with two roosters.  Meat birds are a separate operation, but the extra roasters and stewing hens are a nice addition to our fall meals. 

A stationary timber frame coop is going to turn into a fortress with a muddy moat in 1-year.  Even if you let your birds free range, they will tear up and compact the area around their coop.  You can use chickens to destroy top soil, or build top soil.  The method that you are thinking is great for visual appeal, awful for your soil. 



mattgancz

Dear Michilius:

As I reflected on my post regarding chicken husbandry, I realized that I did not answer the three important questions that you posed.  

First, you asked, " Do I need to dig a foundation down below the frost line for this small of a building?"  No.  I am in Vermont, and historically building much larger than this have been set on a field stone foundation that sits above the frost line.  The key here is that the foundation is dry laid, i.e., no mortar.  If you are married to the idea of a mortared foundation, I would dig below frost line and make a taco out of geotextile that you would fill with crushed stone.  I would throw a drainage pipe in the bottom of the taco for good measure.  You could then build your mortared wall on top.  Essentially this is a rubble trench foundation.  Dry laid is easier, and with this small of a building you can pump it up with a car jack to level it in the future if it heaves.  In regards to the deep bedding, it is going to overtake your sills and rot them.  Deep bedding works because of microbial activity --- that same microbial activity that decomposes the cellulose bedding will decompose your cellulose sills.  Alas, I have already mentioned that this is not a good structure for chickens; you can read my last post.

Second, you asked, "Is this siding structure waterproof with the wood boards alone or does it require some type of caulking or other technique to make sure water doesn't get behind the boards?  Is horizontal siding a safer bet?"  The point of vertical siding is to shed the bulk water, but it is meant to get wet and expand and dry and contract.  Board and batten, tongue and groove, and shiplap all allow wood to expand and contract.  Let it do that, no caulk.

Third, you asked, "Any good sources you all would recommend for how to frame the windows and put in exterior trim with the board and batten in order to make sure this part of the structure is waterproof?"  Buy a copy of Modern Practical Joinery by George Ellis.  



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