NH: How is a half lap joint held together?
I understand about how you've figured it is stronger, but what holds it together? With a mortise and tenon joint the peg holds the cross sill from pulling out of the long sill.

Jim Rogers

Call it a plank frame.....

Hi Jim and all:

First of all let me say that I am only stating techniques used by timberframers from years gone by. I have examined many but not by any means all of the standing frames in my immediate area, but those that I did I paid particular attention to details that was necessary for authentic reproduction, and this included the pinning of joints.

One thing that I have noted is that framers varied widely in their style of pinning and attaching joints

As far as the fastening of corner joints in the bottom mud sills, I did the best I could to duplicate the methods of attachment. What I did to varify the pinning of the corners of a standing frame that I was to reproduce, was to slide in a thin blade and verify the position and number of pins used. In most cases the corners were held with at least (2) 1.5" oak pins, the odd time (3) 1.25" pins staggered slightly. these pins were placed about 2" from the shouldering, leaving enough room on the flat surface, for the mortise of bottom tennon of the vertical corner post.
In most cases the long side sills would pass over the shorter end sills.

It is always a good idea to bore a drain hole in the bottom of the mortises along the bottom sills for drainage should rain water happen to enter the mortise for some reason.

I hope this explanation helps to clarify the techniques that I have to offer on this forum.

NH

I like that! This is also the reason why I'm going with cedar...tends to last through the rain. I recently pulled 4 cedar garden posts out of my mothers yard - they had been in the ground since the house was built (1898), and had minimal rot on the butt ends...!

Dear Timber Godess,

The significance of your post cannot be allowed to pass without comment and note. If your claimed service age for this post is true then this must be one of the longest ground contact timber decay tests on record.

Can I appeal to you to photograph this piece please and do a thorough post mortem on same i.e. check same for timber conversion marks, try and identify original place in tree and size of tree from which it was converted, average growth ring patterns, species (WRC ?)and note the ground conditions e.g. clay, sand, gravel plus annual rainfall and temperatures.

Please let us know more about this post.

Regards

Ken Hume

Yes, Ken, I suppose that the claim of the wood being as old as the house itself may be pure speculation...
I have no photos (this was about 4 yrs ago) but the details are this: My husband and I were digging a new garden. As we were removing the top soil we hit quite a few rocks, and a few treasures; some broken porcelain and an old twisted silver spoon...and a chunk of wood. As we dug deeper to remove the wood (about 4x4) we found it was set into a hole about 3' deep, filled with large rocks. We pulled it out; the bottom and the outside was soft and covered with dirt, but only about an inch deep. The top was similar. It was WRC. The soil is mostly red clay. We used it for a tomato stake.
We pulled another one out from a different corner of the yard...it was rotten through, but in that part of the yard the soil was quite sandy.
The reason I speculate about the age was that the neighbor, an elderly woman whom the street is named after, commented on the fact that she had never seen a fence in the place where we were digging, and she had lived in the house across the street all her life.
Apparently I have a bit too much idealism, in that I tend to believe most of what the old timers have to say without analyzing the reality. ("Well, the lady said such-and-such, and she's an elder, so it must be true...")
I was also going to tell you all about the beautiful pinkish brown cedar shakes found on the bottom layer of the roof we were replacing. They still smelled fresh cut, and had also been there since the house was built.
But, once again, I have no way of verifying that...

Ken and TG

This story makes perfect sense to me. Wood rot is caused by fungi. Before fungi can colonize wood, four requirements must be met: an oxygen supply, temperature in the 40 to 100 (F) range, a supply of sufficient moisture, and a food source (wood). Infection can be prevented by eliminating any one of the requirements. What has happened in this case is that the posts rotted at the margin where they enter the ground and are in contact with the soil but still have access to oxygen. The bases that you found were cut off from the oxygen.
I have seen this phenomenon with WRC fences before. The post has rotted off and you think you are going to replace it where it was, only to find the old post base intact in the ground.
It should also be noted that the tannins in Red Cedar that make it rot resistant accumulate over time so that old growth heartwood is vastly superior in rot resistance to much of the cedar available now.
My bet is those post stumps are as old as you think. Unfortunately there is no lesson here for building because there in no way to avoid the rot at the transition

hI ALL

well I have one also to tell in this regard:

My father who if he was alive now would be 108 yrs young, and one day (1959)as a young man--I was about 20)-- he and I passed by an anchor post (red cedar) set in the corner of a field where he was raised, and he related to me that his older brother had dug the hole and put that post in when he was about 6 years old.

Now this anchor seemed to me to be in pretty good shape and from my calculations about 50 years old at that time. That anchor was removed about 10 years ago by a new owner of the property (1996), and I noticed the removal of it. The lower end was in very good condition, while at ground level it was half eaten away by decay.

The anchor was stoned in if this is of any help as was all anchors that were installed properly at that time,

NH

I am thinking the longevity of the posts set in stones has to do with moisture. I have found old (date set unknown) red cedar boundary corner posts that were almost completely gone above ground but still solid in the hole. They were scribed with owner name and lot # ....which to my knowledge no one does anymore. Packing rocks around the post allows the water to drain away.
So if we make the sills and posts out of rock we should be fine....oh wait, we would have to be masons to do that wouldn't we?

Bob

Hi All posters,

This is a fascinating topic.

I have often toyed with the idea of what it would take to design an all wood foundation and the posts received to date seem to provide both encouraging and cautionary advice.

Most old timber buildings here in the UK have long lost their timber sills with many buildings showing evidence of being righted and underbuilt with more durable materials like brick and stone.

Much earlier, building techniques did employ timber in direct contact with the ground. For example in Scotland and Ireland we have crannog buildings which were built on piled foundations in shallow loch waters with a linking causeway to shore. Below water line some of the timber piles (alder) can still be seen today several thousand years after driving same into the mud.

We have examples of early post (wind) mills where the trestle cross trees and quarterbars (oak)were buried and backfilled to help provide greater stability to the mill. The Saxons were great believers in using earthfast posts and remnants of post circles are frequently encountered

Venice is built on (larch) timber piles.

I accept that the ground / air interface is the problem to be overcome but could we not employ easily replaceable or sacrificial pieces that spanned this vulnerable area made from highly durable timber like cedar, locust, oak, etc.

There also remains the question of treatment and in times gone by charring was employed to good effect as was the application of pine pitch.

I would be keen to get rid of the necessity for the embodyment of high energy concrete foundations.

Any ideas ?

Regards

Ken Hume