Buying sawn boards and calculating waste.

[NOTTNICK]

I am getting close to starting my greenhouse project.
Advice I've received on the project to date has been appreciated.

I am going to order sawn cedar boards - going for grade 2 clear & better. I have a good planer + table saw so can process it myself and hopefully save quite a bit of money.
However, I don't really know how much extra I should be getting to account for wastage.
Looking online I see everything from 10% to 50%
As the basic cost is going to be in the region on £1500, each 10% is quite a chunk of cash!

I've never ordered timber in such quantities before. Also not too sure what I should ask supplier, I guess what they tell me will influence my calculations.

Suggestions appreciated.

Thanks

Nick

 

[Woody2Shoes]

Hi, IME wastage comes from three main sources:

1) Cockups - i.e. cutting a piece wrongly too small by accident (wrongly too large is not usually a problem!);
2) Defects, sometimes latent usually patent, in the timber - knots/shakes/inclusions/weird grain leading to distortion on drying etc.
3) Pieces left over.

Assuming you work carefully, and the timber's of decent quality, item three is the biggest source of wastage. I normally buy a couple of extra pieces to avoid the frustration of having to go back and buy more to get over the fact that I broke/spoiled a piece.

Having a cutting list and analysing, against that list, the lengths of the pieces you start off with to minimise the production of "waste" offcuts is the only way. For example, if you know you need twenty rafters at 2.1m long then buying pieces at 4.2m, or perhaps 2.4m (to allow for snipe and split ends etc. etc.) might be handy lengths to buy.

Do you know what lengths of timber they're offering (or are they "random" lengths - which is a bit more tricky unless you can select them yourself)?
Do you have a cutting list?

PS if you give the cutting list to the supplier they may offer, as a service, pieces to match that list

Cheers, W2S

 

[NOTTNICK]

Hi W2S
Really helpful, thanks.
I do have an accurate cutting list.
Fortunately, if I can get 3300 lengths and a few 4000 then everything works out.
Like idea of giving cutting list - worth paying extra for.
I guess from what you're saying, if the timber is decent and I'm ordering 60 metres, then an extra 3 boards would sound about right (15%).
Nick

 

[RobinBHM]

The most accurate method is to work out the length you need to cover your cutting list and order a few spare.

Softwood is sawn to set widths, ie 2" 6" so unlike hardwoods you know before you order the section you will receive. That leaves a length waste to allow for that depends mostly on what lengths the supplier has in stock.

3.3m lengths is unlikely, 3.6m more common.

Have you tried Brooks Bros for cedar? They are quite a big importer of cedar so might be worth trying.

http://www.brookstimber.com -Danbury branch deals with softwoods


Ive just discovered an importer of douglas fir near to me which I may try soon
http://oakandwood.co.uk

http://stores.ebay.co.uk/frenchoaksleep ... 7675.l2563

 

[LBCarpentry]

No no no don't make life so hard me old boy. Why struggle working these things out when the guys at your timber merchants do it all day long? I order a lot of timber regularly. I used to spend hours working out the lengths and widths needed - RIDICULOUS! Just write out your own personal, accurate cutting list, scan it into your computer (or take a picture on your phone and bung it in an email with the message "please supply me enough timber to achieve my cutting list"

They are very friendly people especially the likes of Lathams and brooks.

 

[NOTTNICK]

I'll call Brooks this morning and report back.

 

[NOTTNICK]

Looks like I might struggle getting thick enough cedar boards.
Lathams have suggested accoya.
I'll start a new post about this.
Cheers.

 

[sunnybob]

If youre making a greenhouse, but cant find boards as thick as you want, are you over engineering this?
First time projects usually are twice as heavy as a professional would make

Ask the woodyards for advice on thickness, they do it all day long.

 

[NOTTNICK]

Good advice.
I'll check it out.
Might save some money too.
Nick

 

[NOTTNICK]

Cool!
I contacted Brooks.
Really helpful. Went to see then today and talked to one of their guys.
Even better - they'll plane it all up for only a very small percentage more than sawn. It'll save me a shed-load of time and be a much better finish.
Just got to bite the bullet and spend some serious cash.
Very happy.