Dry oak in the round

[Crazy Cutter]

Have removed the ceiling in the house and have found the main beam and rafters pretty much shot. House 250 years old and wood is all beech which was a surprise. Anyway has anyone got any dryish oak in the round in my area that i could cut for rafters? or old beams, fence posts to re-mill.

 

Also has anyone got any info on using oak from standing dead trees. The moisture content is always the same the heartwood looks sound but does dead make any difference to strength to use as beams etc. Any help would be great.

[agg221]

The use of beech isn't that surprising if it grows well locally - timber wasn't moved much c.1750 so unless you are sufficiently close to the coast for them to have been using old bits of ship and unless it was a very high class building they were left with what they could get their hands on. There's a lot of poplar and elm used in various parts of the country - our place is mostly elm dating from c.1500.

 

What are the dimensions of the parts you're looking to make?

 

I've almost exclusively used timber from standing dead oak and once even from trees which had been felled and left lying on the ground for approx. 10yrs. All fine. If you have a sense of why the tree died it can help a bit in guessing how likely it is to be sound but in reality there's very little to go wrong with oak - I haven't felled a bad one yet. If they die slowly you tend to get nice dense timber at the edges and less sapwood. Brown timber is slightly more brittle but quite useable for things like rafters and no more prone to being eaten than anything else. I would remove every scrap of sapwood though as it is a magnet for woodworm and it rots really easily - several trees I've done it's been possible to remove it along with the bark, using nothing more than a wire brush! I would also be inclined to apply a generous dose of boron-based treatment to all components, particularly in the joints and the reverse faces which you won't be able to access once installed.

 

Alec

[Crazy Cutter]

Thanks Alec for the reply. I must say your house sounds fantastic. We have lost so much skill compared to what they were able to do with not a lot. Too much waste in building today and too much treating wood as plastic.

 

The house is late 18th century but was part of a large estate so would guess beech was being planted as the forestry era had started. Most other woods were still coppice, a lot of the houses here are elm or oak.

 

We have opened the main fireplace stack (huge 9' by 8') which has a lovely curved beech lintel but axed to make it more curved and axed to square it. then the carpenter has sawn all the joists and main beam. I would have thought with their level of skill he would have axed the joists? The joists are soffited into the beam, so with movement and drying there is only an inch of every joist into the beam! Woodworm and a very large one at that (4-5mm exit hole) has eaten into everything beech and pine that end of the house. The fireplace lintel is fine though (charring)?

 

I have a dead oak beam cut to match 17' by 8" by8" but was concerned about using a green beam due to movement etc on old norfolk brick walls. Trying to find an oak with a straight grain has been a nightmare. Have also now found some lovely un rotten oak gate posts in a barn so will be able to re-cut them with the small log mill for the joists. That will be it till next summer giving me time to cut new beams, joists etc and get them a bit drier.

 

Will still require old oak if anyone comes across any as we have plenty more to do within this house!

[Crazy Cutter]

Pulled some more apart today. It is death watch beetle as has only attacked the beech and oak but has bored through pine board to pupate. All the beech and some of the oak is like dust. The walls have been damp in the past so it was ideal for it but haven't found any living beetles yet.

[agg221]

I wouldn't be too worried about a green beam - assuming it's resting on brick walls on the ends and maybe the middle. There will be very very little shrinkage along the length, almost all in the width/height, so it might open up gaps if it's mortared in but should otherwise be fine. The original would probably have gone in green - I doubt they would have waited four years for it to season!

 

Fortunately we haven't had any deathwatch here - just the standard woodworm, but I don't think they enjoy the dust dry elm very much. We're also thatched and about the only thing that goes for that is the mice. I think the problem with 'green' construction materials is trying to find a way to defeat the natural agents of decay, or at least slow them down as much as possible.

 

How big are the joists and rafters you need to make?

 

Alec

[Crazy Cutter]

 

How big are the joists and rafters you need to make?

 

Alec

 

All joists and rafters are 4 x 2 or thereabouts everyone being out and usually waney or bowed. Length joists 6 foot and rafters 10 but don,t need many of them mainly joists.

Edited August 6, 2012 by Crazy Cutter
added bits

[agg221]

Most of my spare stuff is a bit heavy at 3" and a bit wasteful to resaw, but I'll keep you in mind once I've got my extension rafters and studwork installed and know what's spare. I know what you mean about waney and bowed - we have an inserted upstairs from the 16th century(originally built as an open hall house) and one half is the original insertion which was designed to be seen so is fairly square, the other half is a later (c19) replacement which was originally plastered over and the joists look like bits of hedge!

 

Your earlier comment on squaring with an axe vs sawing - I think it depends on whether they're box heart or not. Squaring up a box heart beam with an axe/adze makes sense, and it's still the best way to make the curved sections, but if you're splitting down a larger section it's less wasteful to saw them to get a true surface. You need at least one true surface for the top, sometimes a second one on the lower side if it's designed to be plastered over (look for the little nail holes if they're currently exposed). Early joists and rafters tend to be split (cleaving) up the centre, so you cleave along the straightest line, meaning they have the maximum sideways bow. You then clean up the lower face and the sides to as true as you can get, using an axe. The timbers therefore end up wider than they are deep, which isn't very structurally efficient. If you saw them out though, every face is true and you can make the timber deeper than it is wide, which is more efficient in use of timber.

 

Our early c19 timbers are all sawn, the c16 and c17 ones are all cleft/axe finished. I wonder in your case whether it relates to being part of a large estate which may result in deliberate forestry and hence labour for moving logs and a saw pit?

 

Alec

[Crazy Cutter]

 

Our early c19 timbers are all sawn, the c16 and c17 ones are all cleft/axe finished. I wonder in your case whether it relates to being part of a large estate which may result in deliberate forestry and hence labour for moving logs and a saw pit?

 

Alec

 

I would hazard a guess that's why they used beech. I have two more rooms to go next year which each have a 17' pine tie beam so i would guess are going to be rotten at the walls but maybe a later addition. The floor joists are again all beech from what i can see but without deathwatch and maybe later as look far better (i can only see the ends!) The house was originally thatched with a steep pitch down to lower window height and then an upstairs added. Walls are thin compared to original but pine roof timbers all good so that's a bonus.

 

When we removed the reed ceilings the original plastered ceiling was underneath, between and over the joists with lovely khaki colour as good as the day it went up and a pain to get down. There were three pine laths running between the joists to hold the plaster on and nailed to the floorboards. They were able to split scots pine over 6 to 8' down to 4 to 6mm thick!

 

No problems with your thatched roof i hope. They become costly when others haven't done any upkeep.

[agg221]

Thatch on ours isn't too bad thanks - we're in a long straw area so regular renewal of the top layer is needed anyway, but we budgeted for the first maintenance and first re-thatch when we took out the mortgage.

 

I've cleft 8' lengths of sweet chestnut to 8mm but I really don't fancy that job with scots pine!

 

Sounds like your listed buildings officer (I presume you're listed?) is rather less picky than ours. We would have to patch up absolutely everything feasible and insert new timbers alongside old ones if they couldn't be suitably repaired. Not sure where things would stand if we needed to take down a ceiling to access damaged timber underneath - it could be an interesting conflict of interest. We would also have to replace like-for-like as to species, although I suspect that they may not be able to identify that many species if I didn't volunteer the information.

 

Alec

[Crazy Cutter]

 

Sounds like your listed buildings officer (I presume you're listed?) is rather less picky than ours.

 

Alec

 

No not listed these are ten a penny in this village, so more lucky than you. We couldn't see any other way to do things than take the ceiling down. No one else was interested in buying the place so that must say something?

 

My brother is a reed thatcher, done quite a few jobs with him when younger and they last when looked after. My job was always pointing brotches then i moved on to hazel cutting hence the interest in coppice and timber framed building.