UKH

Advice please on the easiest/best way to do this - and also what tools are required (which I may or may not already have).

I've got 6 lengths of wood - all 60-90 cm long, cross section 38x47 mm.

I want to "angle" the cross section so that it's 32mm on one side & 26mm on the other with the "angled" top being flat (but obviously all at an angle). The photo shows before and "after".

Application is for a new roof on our brick "shed". So the angled surface can be rough but it needs to be as flat as possible.

The one I've "done", I used a plane and a rasp but it takes ages and it's very difficult to get it flat over the whole angled surface - the photo shows that I've not got it completely right yet - there must be a better way - so I thought I'd ask the "all-encompassing" UKC hive-mind.

If you have two old timbers, you could make a stepped base, clamp the work piece between two old ones on that base and use the old ones as references surfaces to help level your tools.  Then when you’re finished you’ll have a 3-piece uniform slope.  Perhaps rough work the part first and finish in this jig.

Or, make 3 rough worked pieces, clamp them on a stepped base and use them as guides for each other.

Stepped base can be cut using sections through any old timber.  A bit of trig will tell you how much to raise each part by.

Do you have a mitre saw?

I think the easiest and probably the most precise way to do that would be on a table saw.
(You did specifically include tools you may not already have.)

Any chance you might find someone near you who has one in a workshop?  It would literally be a five minute job.

Go to your nearest pro joinery shop-they will do this in  about 20 seconds on a dimension saw for you, probably cost a tenner.

Obviously don't know how the structure is made, but mightn't it be easier to do the adjustments on the underside fixing points so that the timbers sit at the correct angle without the need for cutting?

I'm a carpenter, do you have a drawing to better understand what exactly what you're trying to achieve? A quick pencil sketch would be good ebough

I would use a tablesaw, but before I had the tablesaw I would have planed it to size. Actually given it would take 20 minutes to clear space around the table saw I may well use a plane anyway!

The tricks to planing are work holding and not trying to take off too much in one go, also if your plane isn't sharp it will take forever. 

Have a look on youtube for the 'scary sharp' plane sharpening technique, no complex jigs and tools required just some half decent sand paper and a bit of patience. 

What are you using to hold the wood while you work on it?

Or put triangle wedges under the timber where it meets the brick wall and keep the timber intact

Unfortunately not

No table saw - and I don't think I know anyone locally with one (*) - I knew it would be a trivial job with the right power tools - unfortunately I don't have those.

* - have a friend back in Leicester who has all manner of "toys" that would probably make this task trivial but 100+ mile trip each way isn't really on 😁

Quick description - brick "shed" roof:

1. One long wall is (now) 3 brick courses higher than the other long wall (winter with low temperatures, crap weather and old, not quite uniform bricks is not the best way to learn about bricklaying!)

2. Piece of timber (2.4m x 95mm x 50mm) to sit on top of each of the long brick walls. With angled cut-outs to take...

3. 4 pieces of timber (1.8m x 47mm x 38 mm) sloping down from one long wall to the other long wall. On which will sit...

4. Polycarbonate roof (unfortunately too big for 1 piece so in 3 sections)

But, the 2.4m timbers haven't got enough depth for the cut-outs to allow the sloping 1.8m bits to be fully recessed, so there will be a gap running along the top of the 2.4m timbers and below the sloping polycarbonate roof.

These bits I'm trying to sort out are basically to fill those gaps and provide some extra places to fix the polycarbonate - so the bottom needs to be flat horizontal and the top needs to be flat angled to match the slope of the roof.

I did think about using wedges between my cross timbers (which will be lying flat on the bricks) & sloping timbers but decided to do some cut-outs and partially recess them instead.

The gaps would have been larger with wedges so I would still have had the same problem.

I suspect the end result of all this will be an over-engineered structure/fixings a la Forth Rail Bridge. The main lesson I've learnt is to pick the right season ☀✔❄❌❌❌

The vice in my B&D Handyjack (step ladder - work vice combo) - not ideal

I can get the angle about right, the problem is that the end result isn't uniformly flat, and it's difficult to stop the surface becoming slightly convex.

I'll have a think about Wintertree's stepped base and working on several lengths at a time - see if I can cobble something up. Should have spare bits of timber from the old roof - if they haven't all rotted away (some of it just crumbled in your hand to "compost").

Dare I suggest squirty foam for gap filling?

Table saw is quickest. I don't have one so in the absence of a different solution I'd consider the following:

Circular saw with guide, carefully screw the batons down to scrap in the vise to hold them.

Notch every 40mm or so with a hand saw then knock the blocks out with a chisel.

Plane.

Who am I kidding, I'd grab the foam gun.

Jk

If I'm correct you're trying to achieve the same pitch with your bearers as your rafters. In that case could you not just bed your bearers on with mortar to achieve the correct angle, and use joist hangers to support your rafters. 15 yrs as a builder and that's the way I'd go. 

Could you not cut an angled notch for each rafter in the bearer lengths, angle cut the ends of each rafter to vertical and then fasten a vertical plank along the rafter ends to close up all the gaps.

Just need a basic saw and mallet + chisel then (and some time)

Mark

Your angled notches are my "cut-outs" - I didn't know what the correct terminology was, yours sounds better.

If you mean bit like a fascia board, then I could put one on but it wouldn't fill the gaps because the rafters will extend beyond the bearers cresting an overhang. It would just hide the gaps a bit.

I presume your bearers are my bits going along the walls and the rafters are my sloping bits going across the gap. I wasn't sure of the terminology for all the bits so thanks for that.

The bearers are flat and already have angled notches (what I called cut-outs) that allow the rafters to sit on the bearers at the correct angle. But since the rafters won't be fully recessed (bearers not deep enough), their top surface will run above the edges of the bearers which will leave a horizontal gap (approx 20mm) all along the bearers between each pair of rafters.

So I wondered whether having those gaps would be a "weather" problem. The shed doesn't need to be watertight dry, and my understanding is that it's not too much of a problem if bits of the wood get wet as long as they have air and can dry (the previous tiled roof rotted because it got wet and the wood was enclosed between the tiles and a polythene membrane). Also the roof will overhang by about 150mm so the weather would have to be quite windy for rain to blow straight through.

Anyway, I was going to put a small "wedge" in each inter-rafter gap to provide an additional fixing mid-point for the polycarbonate roof panels. Then I thought I could lengthen those wedges to pretty much fill the gaps - which is where I'm at now.

After the quotes we got I was trying for the low-cost DIY solution but the £ are gradually going up 🙁

Whats wrong with a facia board on the ends hanging down and another board fixed to the underneath of the overhanging rafters

Could do, but it's getting more complicated all the time - although I can see it would avoid my current problem.

Actually could just fit a facia board to the bearers (since they're the same width as the bricks), but it would need small notches cut out for each rafter (since I've already cut out notches in the bearers for each rafter).

Something I realised earlier when I was planning was that with a sloping roof, there is always going to be one bit that isn't straightforward.

This makes sense, if your bearer notches aren't cut down at all on the outer edge, then a bit of fascia board screwed into the underside of the bit of rafters overhanging the wall will close all the gaps and keep the weather and wildlife out. 

It would just need to be a single width strip that butted against the bearer and the inside of the vertical fascia on the end of the rafters, you'd want this coming down lower than the bottom face of the rafters anyway.

If you work the rafters length out properly, these fascia could be standard width trim strips, look somewhere like Eurocell plastics for strips, lots of length / width options available. 

Mark 

I'm not sure what the spec on your construction is but if you were to insulate and board the ceiling indoors then a continuous air flow like you have created would be essential. For a neat finish a ventilated soffit and fascia could be added.

If you want the rafters extending and you don't need the ventilation but would like a neat finish, then your stuck with cutting sections to clad. Or... the traditional finish for extended rafters with no soffit would be just to brick the gaps in between the rafters, in this case the rafters normally sit on a bearer on the internal leaf (as is usual with most designs) but if you've only got a single leaf then there would be no harm sitting them directly on the masonry (you'd probably want to add noggins on the other side of the wall to stop any twisting though)

https://www.toolstation.com/einhell-2000w-250mm-table-saw/p47537

£100 for a cheap table saw. I bought one 20 years ago and though it doesn't get much use its really handy to have available. 

I'd need somewhere to store it, maybe a shed with a roof on 😁

It would probably be easier to 'birdmouth' the rafters - cut notches in them so they sit on the walls properly.

https://www.diydoctor.org.uk/projects/birdsmouth.htm

I thought about doing that but the rafters are relatively small (38x47mm) - not like proper house roof rafters - any notches would potentially weaken them too much. But I can see what you mean that it would be much easier to cut notches in the rafters rather than in the bearers.

The polycarbonate roof will be pretty light so for rafters, I got the smallest cross section timbers that I was happy wouldn't bend under the light weight they would be bearing. The whole thing doesn't have to be strong, it just has to stay there 😁

I would have thought you'd make a perfectly adequate job of it with a simple ripsnorter (circular saw) set to the correct angle. It isn't like it needs a cabinet-maker's finish.

What you should have done was ask the question before buying the rafters and bought deeper ones you can birdmouth . Maybe the 'measure twice cut once' saying needs to be amended to 'ask UKC, measure twice, cut once'?

Alternatively you could double them up if light isn't important?

This would definitely be easiest in a joiners workshop, but if that's not possible a saw like this would be my choice to do it at home https://www.screwfix.com/p/evolution-r165ccsl-1200w-165mm-electric-circular...

Do a bit of googling to find one with appropriate features/price, I've got a Skil that was fairly cheap but came with some guide rails that I use for all kind of jobs.  More versatile and easier to store than a table saw 

If you do buy one, be careful with it, they can remove fingers very quickly, which won't help your climbing

If my understanding of your build is correct, I'd either cut slots in your existing brickwork or lay an extra course at both ends and bed the rafters in said brickwork.  Finish off with foam filler and sticky flashing.