Am I being picky?

[DrPhill]

We are staying in a converrted/renovated barn for a few days break. It seems that they straightened the roofline at one time. I was not entirely reassured by the workmanship....

What I was actually wondering though, if this had been made from a single piece of timber, would the grain have been better running perpendicular to the main beam. With the grain in line with the beam the grain line would always be a weakness.

(Edited several times to get the image right....)

 

[AJB Temple]

Ha! I have owned a lot of old barns through my life. Mostly they were hugely overbuilt structurally and the skill doing joints off timbers that were not remotely square or straight was considerable. But so many are still standing. I live in one dating from about 1680 and the timber sections are mostly about double what we would specify today. Jointing is rough and ready - but given that it has survived over three centuries I suspect it is passable.

 

[ScaredyCat]

You've seen how modern houses are built, right?

.

 

[Lons]

You've seen how modern houses are built, right? .

What he said. :lol: At least as far as bog standard estate houses are concerned.
As a retired builder who's worked on old and new I know which I'd have more faith in structurally.

 

[Trevanion]

You've seen how modern houses are built, right?

.

There's been some new houses (About 20 or so) put up locally lately, they had to tear one down (Not sure at what stage they were at put it was pretty far into it) and start completely again because the worksmanship was so shoddy and not up to scratch. What a great advert for the rest of the houses!

 

[Some bloak]

Ha! I have owned a lot of old barns through my life. Mostly they were hugely overbuilt structurally and the skill doing joints off timbers that were not remotely square or straight was considerable. But so many are still standing. I live in one dating from about 1680 and the timber sections are mostly about double what we would specify today. Jointing is rough and ready - but given that it has survived over three centuries I suspect it is passable.

Quite true. My house was built/rebuilt on the site of an old longhouse that crumbled to the ground over 150 years ago. However, the barns I have are all original and pre-date the house by hundreds of years. They seem to have built better and had more respect for their barns than their houses around her.

 

[DrPhill]

I hear what you are saying, and agree - the old jointwork on the frame is impressive. The structure may have been standing 500 years, supporting roof 'tiles' which are 2+" thick cotswold stone. The mortice and tenon joints are still snug, and most are still pinned with 'dowel'. (How did they drill the holes? red hot poker?).

My concern was the relatively feeble looking triangle of timber preventing the lifted beam from sliding down/right in the picture. I do not know what holds it on to the big beam, and it is already splitting (both sides) exactly where I would expect the most stress to be. It would be the modern skill and quality levels being applied to an old building that would concern me, not the old building itself.

 

[Bodgers]

You've seen how modern houses are built, right?

.

I don't think bad build quality is the sole preserve of new builds.

There always have been bodgers and corner cutters.

I've lived in a couple of new builds. This one I own atm is actually pretty good. The only issue has been a slightly twisted side door casing and some messy rendering on one wall.

The standard of internal fittings and fixtures blows away something like my parents 1960s semi.



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[Woody2Shoes]

We are staying in a converrted/renovated barn for a few days break. It seems that they straightened the roofline at one time. I was not entirely reassured by the workmanship....


What I was actually wondering though, if this had been made from a single piece of timber, would the grain have been better running perpendicular to the main beam. With the grain in line with the beam the grain line would always be a weakness.

(Edited several times to get the image right....)

I think that the extra piece they put in is perfectly reasonable. If you look at the notch in the main beam, where (I guess) the purlin used to sit, there's a similar amount of timber in a similar orientation stopping the purlin sliding down the roof.

I'm not a structural engineer, but the main force downwards is tending to bow the rafter and the main component of that downward force is perpendicular to the rafter. This is why the thickest section of a purlin is normally placed perpendicular to the rafter, not parallel with it or vertical. The component of the downward force, parallel to the rafter, tending to make the purlin slide down the rafter, is relatively small by comparison.

When comparing old houses and new ones I think it's important to remember that the only old ones we tend to see are the "survivors"!

Cheers, W2S

 

[DrPhill]

Thanks for the replies.... I am surprised by the general feeling of 'thats normal', but I am not a structural engineer.

If I were buying a house and saw that work in the roof I would be concerned - certainly enough to get a second and third opinion.

Woody, I hear what you say about the amount of wood supporting the cheek of the purlin being the same, but in the new material this support is only backed by eight or ten inches of timber and whatever holds that triangle to the main beam. The original support was backed by several (maybe ten) feet of timber integral to the main beam.

But an interesting discussion and yes, I am known for over-engineering. Someone defined an engineer as 'someone who can do for a penny what any damned fool can do for a pound'. Perhaps I am that fool using far more material than really needed.