Help, Chimney 'knee' construction

[Post and beam]

I need to construct a frame i guess onto the knee of my chimney. Roofer wont do 'chippy stuff' and the Brickie doesn't know either. Its too small a job apparently, to get a chippy in to do it.

So i need to learn what and how.

Can i lay a piece of 4 x 2 onto the slope of the knee with a corresponding piece on the inner SIP panel face such that Battens can be installed across just like the main roof?

 

All help and knowledegable comments gratefully absorbed as allways guys

 

Thanks in advance

 

keith

 

 

[Nickfromwales]

In a nutshell, yes, as you describe.

 

Needs to be treated timber, and you defo do NOT want to be drilling and fixing into the diminished section of the bricks or you'll crack / break them out most prob. You want to be drilling at 90 degrees to the timber and have the holes placed so that the drill is impacting just below each mortar line, eg into the meatiest part of each brick and NOT into the 'tail'.

 

Cut that counter batten off and tape up the holes, then install the wall plate to match the timber atop the bricks, and the rest is history. Roofer should be able to batten and membrane etc from there, after you've changed his nappy......

 

Can't see any lead or other flashing? What's going to sort the break between the roof and the bricks? 

[Post and beam]

12 hours ago, Nickfromwales said:

Can't see any lead or other flashing? What's going to sort the break between the roof and the bricks? 

Hi Nick, The upper half of the gable end will be Hardie weatherboard. I think i need to fix some kind of batten to the SIPs panels (to the studs within) that the lead can be dressed over. Then the hardie can sit over that.

[Nickfromwales]

45 minutes ago, Post and beam said:

Hi Nick, The upper half of the gable end will be Hardie weatherboard. I think i need to fix some kind of batten to the SIPs panels (to the studs within) that the lead can be dressed over. Then the hardie can sit over that.

Needs a decent bit of thought and some robust methodology then tbh.

 

The lead should already be in the brickwork of the chimney, should it not? Who’s coordinating this? 

[markc]

As above, the chippie bit of this is simple stuff, getting the lead/flashings right is the important part.

[Post and beam]

6 minutes ago, Nickfromwales said:

Who’s coordinating this? 

Unfortunately that would be me. I dont have a primary contractor/ builder.  So it is down to me, which is how i have ended up with the situation i have.

[Nickfromwales]

1 minute ago, Post and beam said:

Unfortunately that would be me. I dont have a primary contractor/ builder.  So it is down to me, which is how i have ended up with the situation i have.

I think you need to lean on the roofer here, as there should be part plastic lead skirt ‘trays’ that are installed onto the SIP and emerge from under the hardie.

 

Cant think of the bloody name for them.

 

Something like this but not for a cavity

 

 

 

And for the sides of the chimney you need to grind out the mortar lines and take out the corners so you can fit these type of things. 
 

 

This isn’t for the feint-hearted tbh, it’s a lot of work and you can’t get this wrong, particularly where the internal angle of brick flashing meets the one on the gable.

[Nickfromwales]

I guess the gable flashing could be simplified and done with a single length of very wide lead flashing, with that mechanically affixed to the SIP and left turned up ahead of the roofing work. Then it simply gets dressed back down onto the roof (tiles / slates?).

 

I’d probably want to use a self adhesive flash band to cover the top of the lead, where you’ve installed the fixings through it to affix, just to make it bombproof against water ingress. To be clearer, once the lead is flat against the wall, you’d have the open edge of the lead facing up, so that prob would benefit from being covered over by the flash band.

 

 

Would prob need at least a 600mm wide roll of lead I think, but I am dumbfounded that your roofer hasn’t just pushed you out of the way and just simply got the f@ck on with this. It’s nuts tbh.

[Nickfromwales]

Just to add some more salt, you need to work out what will happen to the open end of the membrane / batten / tile (at the top edge of the rising sloping brickwork) as the dimensions to work to there will affect how far in / out the lead chimney skirt is set in.

 

There’s a lot going on here, sorry to pickle you. 

[Post and beam]

40 minutes ago, Nickfromwales said:

There’s a lot going on here, sorry to pickle you. 

Nick i am so grateful as always. Dont worry about giving me too much info. I would much rather get it straight with loads of detail and then i can research the terms i dont understand.

 

The roofer was the same when Potton left some of the timber dormer ridges unfinished and the valley noggings in the dormers. He said ' you have a weeks worth of carpentry to do' . What he has done is good and i love the look of the roof but its left me to figure stuff out that i am unqualified to do. 

My fault for not employing a main builder or project manager i guess. 

Having said that, i figured that i could afford to make 2 mistakes at £10k each time and still come out ahead of the alternative.

Thanks again

[Nickfromwales]

Keep asking questions and we’ll all try to keep answering them 👍🙂

[Post and beam]

I am thinking something like this to start.

Yellow lines represent 4 x 2. Screwed to the studs within the SIP's plus anymore lower down.

Green line represents a vertical length of 4 x 2 screwed to the chimney bricks as support.

Something to run horizontally across the top at an appropriate point.

 

That should do it for strength?

[Russell griffiths]

26 minutes ago, Post and beam said:

I am thinking something like this to start.

Yellow lines represent 4 x 2. Screwed to the studs within the SIP's plus anymore lower down.

Green line represents a vertical length of 4 x 2 screwed to the chimney bricks as support.

Something to run horizontally across the top at an appropriate point.

 

That should do it for strength?

Not really, that’s all a bit wrong 

are you after building the timber work to support the roof tiles ?
if you are then we need a bit of clarity on what you want to achieve 

will you have a barge board running up the outside of the brickwork, or will you just over sale the tiles and have a cemented fillet, or dry verge. 
 

what roof covering is going on this ?

 

will it have a soffit and facia at the lowest point, or just facia. 
 

need a sketch reall on what the final goal will be then I can guide you as to how to frame it up. 

[Post and beam]

1 hour ago, Russell griffiths said:

that’s all a bit wrong 

Thats why this forum is soo good. Thanks.

# Yes trying to provide a stable platform for the roof tiles. Clay tiles as per the main roof.

# No barge board on this little piece, slight overhang and muck to tidy and seal the edge.

# No soffit or facia. The main house is open eaves.

# As its such a small area i was expecting to overhang the tiles at the bottom edge and let the rain drip into fresh air.

 

Thanks again

 

keith

[Russell griffiths]

It’s going to be hard to explain 

you need a rafter fixed into the sips panel like you said, the top end of this rafter will fit flat up against the a ledger board that needs fixing to the side of the c—————

sod it I will try to find some pictures. 

[Russell griffiths]

 

does that help, the bottom of the rafter is supported on a timber fixed on the inside as the roof tiles in this instance don’t have any rafter tails on show. 
 

if this helps you need to do a mock up to see how you want the rafters to finish and how you want the tiles to sit over the brickwork. 

[Post and beam]

Hi Russell, it helps hugely actualy. It shows lines, end detail and the 'proudness' of the forward most piece of timber relative to the stonework.