Hello, hope this post is in the appropriate forum...was wondering if anyone could give me some advice/opinions about setting a 4x6 pressure treated post in the ground: I plan to set in concrete an 8 foot, 4x6 pressure treated post 4 feet into the ground and then attach a 16 foot 4x4 post onto that which will have a 30 pound bat house attached to it. I was going to attach the 4x4 to the 4x6 with 2 inch galvanized lag bolts—4 of them spaced at 12 inches. I am hoping this 4x6 supports the 16 foot 4x4 being in the ground 4 feet although I have read that it should be much deeper. Ultimately, the bottom 4 feet of the 4x4 post with the attached bat house will be secured to the 4x6. Any thoughts are appreciated!
Gus64
It should be fine, maybe over kill?
I would do the following before setting the post down the hole. The depth seems fine, but put several inches of small stone in the bottom to prevent water from pooling at the bottom. It depends on the type of soil you have in your area and you will find out when you dig the hole. Sand and gravel will be better than wet clay. I would also seal the bottom 24" of the 4 x 6 post with tar or spray on underbody coating. I've done this for about 100 4 x 4 fence posts and about 50 or so 4 x 6 deck support posts. It's cheap "insurance" to help prevent rot. Be sure you get the "underground" pressure treated posts, not the "on grade" type. :vs_cool:
I would do the following before setting the post down the hole. The depth seems fine, but put several inches of small stone in the bottom to prevent water from pooling at the bottom. It depends on the type of soil you have in your area and you will find out when you dig the hole. Sand and gravel will be better than wet clay. I would also seal the bottom 24" of the 4 x 6 post with tar or spray on underbody coating. I've done this for about 100 4 x 4 fence posts and about 50 or so 4 x 6 deck support posts. It's cheap "insurance" to help prevent rot. Be sure you get the "underground" pressure treated posts, not the "on grade" type. :vs_cool:
4" x 6" seems like overkill (and heavy). A 4" x 4" post would be plenty strong enough for a bat house.
Every spring the local newspaper prints plans for bat houses and recommends their construction. Apparently this is more important than ever because of Lyme Disease, West Nile disease, etc. The bats help control the mosquito population.
https://www.mosquito.org/page/diseases
According to Sagulator you could place a 4" x 4" piece of PT lumber on cinderblocks 6 feet apart and load 900 pounds on span and have a deflection of 0.20" (1/5").
I don't know what your bat house is going to look like but I suspect that a 4" x 4" would be strong enough and lighter and easier to carry and install.
Every spring the local newspaper prints plans for bat houses and recommends their construction. Apparently this is more important than ever because of Lyme Disease, West Nile disease, etc. The bats help control the mosquito population.
https://www.mosquito.org/page/diseases
According to Sagulator you could place a 4" x 4" piece of PT lumber on cinderblocks 6 feet apart and load 900 pounds on span and have a deflection of 0.20" (1/5").
I don't know what your bat house is going to look like but I suspect that a 4" x 4" would be strong enough and lighter and easier to carry and install.
A post set in packed gravel will last much longer than a post set in concrete. The concrete retains water and the post will rot right at the top of the concrete.
If the gravel is well packed, the post is just as rigid as one set in concrete. And, when it does come time to re-do it, it will be a whole lot easier to get out.
If the gravel is well packed, the post is just as rigid as one set in concrete. And, when it does come time to re-do it, it will be a whole lot easier to get out.
Lyme disease is a tick-borne bacterial problem. Bats can't help.
Every bat house plan here supposes that the bat houses need to be mounted on the warm side of your house.
Just rig it up so the bat kaka falls unnoticed and not into your chip dip.
Any kind of a wooden pole support is too easy for cats to climb and kill off your bats.
Lower the bat houses, cats can't climb walls, keep the bats hunting where you sit.
They don't interact with people.
I have a second floor balcony off my dining room.
It is one Hello of a flying leap up there from the neighbor's fence.
A couple of cats are regular visitors, all the same.
Every bat house plan here supposes that the bat houses need to be mounted on the warm side of your house.
Just rig it up so the bat kaka falls unnoticed and not into your chip dip.
Any kind of a wooden pole support is too easy for cats to climb and kill off your bats.
Lower the bat houses, cats can't climb walls, keep the bats hunting where you sit.
They don't interact with people.
I have a second floor balcony off my dining room.
It is one Hello of a flying leap up there from the neighbor's fence.
A couple of cats are regular visitors, all the same.
There's an easy "fix" .......
Just slip a piece of 6" thin wall PVC on the 4 X 4 post before you bolt it on. Stove pipe will work also. You can also retro fit it if the bat murder rate increases to the point the bodies start piling up around the base of the post. :vs_OMG:
Just slip a piece of 6" thin wall PVC on the 4 X 4 post before you bolt it on. Stove pipe will work also. You can also retro fit it if the bat murder rate increases to the point the bodies start piling up around the base of the post. :vs_OMG:
Hi Gus,
Looks like your already well into this project and have little to do than get it into the air?
I will assume you are just following standard "web base" plans for generic bat houses also.
I will add to others advise here...NO CONCRETE!!!..it will last longer and be more secure with just well packed rock and gravel around its base.
You can also extend the life span of the PT wood by charring the outside portion that goes into the ground and there are also "borate" and/or decay inhibitor "pills or plugs" that can get drilled into the wood at a later date should you wish or need more protection. PT wood is not as "rot resistant" in many of its forms as it is advertised by the manufacture.
If your design for the Bat House doesn't work as intended, don't hesitate to come back here for more assistance or drop me an email. I'm no longer an active member of BCI (Bat Conservation International) but once was in a professional capacity. Should you want to look at other examples of bat houses, check out "Chiroptera Architecture," for some ideas...I update it once or twice a year...:laugh2:
Good luck!
j
The suggested method of putting treated posts in the ground is to back fill the hole with gravel. I've never done that though. I've always put them into concrete. I build pole barns for shop space and use the 4x6 posts for that purpose. I had one building destroyed by a storm but the posts were fine. They were only in the ground 3' as at the time I built the building I was digging the holes by hand. Anyway I dug up the posts, broke the concrete off the wood and they were in great shape after 25 years. I went ahead and reused the posts to rebuild another building.
Treated wood is also suppose to be corrosive to metal parts but I've never had any problems with lag screws.
Treated wood is also suppose to be corrosive to metal parts but I've never had any problems with lag screws.
Yes, I built a 4 house chamber from the batcon site...was a fun, winter project I did with my stepson.
I do know it is suggested that you install a post in ground at least 1/3 to 1/2 of the length of the piece above ground and I am less than that recommendation. I think I would have to hire someone to dig an 6-8 foot hole so I am going to put the 4x6 in at 4-5' deep and hope for the best. I guess that's where I thought 8, 50 lb bags of concrete would give me a heavier base. Can always swap them for, say, modified stone? That packs quite well...
I love having bats around, but another thing bats need is a nearby source of water. We had the most bats the summers we had an above ground pool for the kids. The bats would swoop down and skim just above the surface and dip their mouths into the water. We have a stream about 250 ft behind the house, and I have seen them skimming the water there too. I put up bat houses, but they have never been used. I have a few "den trees" not too far from the house, and I think they reside in those. One is a huge old poplar with lots of holes and hollows. I know I have seen owls and raccoons using the lower holes.
I was taught to insert metal brackets in the concrete, then bolt the posts to the brackets. Around here, you don't want to put wood directly in concrete. Even treated wood won't last. You can find them at the big box hardware store. Go there to look at the assortment of different choices. Here is an example, but the ones we used recently are much heavier looking:
https://www.strongtie.com/standoffpostbases_castinplacepostbases/pbs_base/p/pbs
https://www.strongtie.com/standoffpostbases_castinplacepostbases/pbs_base/p/pbs
After doing some research .....
I found several articles on why NOT to fill the post hole with concrete:
This title is misleading, it should have a ? at the end!
https://www.portersbuildingcenters.com/fill-that-post-hole-with-concrete/
I personally do not fill the holes with concrete. I put gravel in the bottom, tar or coat the part that goes into the ground then pack the soil and tamp it all around the post. :vs_cool:
I found several articles on why NOT to fill the post hole with concrete:
This title is misleading, it should have a ? at the end!
https://www.portersbuildingcenters.com/fill-that-post-hole-with-concrete/
I personally do not fill the holes with concrete. I put gravel in the bottom, tar or coat the part that goes into the ground then pack the soil and tamp it all around the post. :vs_cool:
The 4x4 posts for my pool deck are in concrete. I have lived here over 23 years. So far, so good.
I always set them in concrete but then I'm in a pretty dry climate. Slope the concrete away and wrap the bottom of the post with a copper band. As it oxidizes the copper solution that washes down kills all the rot which always starts right at grade.
Attachments
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
