Nickfromwales

Ok. My question was aimed at if it was a boiler / fire ( aka deadly ) flue, I should have been clearer. . I was just going to give you chapter and verse TBH, like stop denting / damaging it for one, but if it's just a humble extractor duct then it's not an issue. . Much better pic. If we can see the whole 'picture', the advice will be better .

Is that a flue liner @Dee? Can we have a wider angled / zoomed out pic please? Ta.

Tres bien. I'll order that, as roof cuts are the final frontier as far as my skill set goes. Currently mastering the nemesis that is staircases at mo as I'm trying to bag more garage / attic conversion / extension work this year.

As much as possible TBH. The more the better afaic, and if ordering the new timber at 4.8m then there's your overlap ( 6.0 - 4.8 = 1.2m tail end ). If ive got the right end of the stick that is .

@PeterW that first link just refreshes BH Is it just my end? Can't get any sense from it. ?

It's no different to how a regular heating and hot water system is plumbed. The heat source ( ASHP ) produces heat, and it gets pumped out. That flow goes to a diverter valve which has 3 ports..... 1) heated water in from HP 2) flow to UFH / buffer 3) flow to DHW / uvc When the demand is for Ufh, the unit idles at low temp / max CoP, but when the UVC calls for heat ( cyl stat and / or 'boost' controller ) then flow to the Ufh is completely isolated and the HP ramps up to say 55oC to heat the UVC only. When the UVC is up to target temp, the diverter redirects flow away from the UVC, back to the Ufh, and lowers the temp accordingly. The ashp gets a trigger signal, either from the 3 port valve or cyl stat, so it knows when to alter the temp range.

@Dee Are these part vaulted ?

Dee, have you mentioned that your a brave self-building lass yet . Avatar please ! And are you really doing the dormers ? I know you can drive an excavator so I won't be one bit surprised TBH.

Crossed posts

A ridge board isn't load / weight bearing. A ridge beam is. If your making a 'cut' dormer then your looking at triangles, with the bottom horizontal timber being your ceiling rafter. If that's the case, and they're not vaulted, then you don't need a ridge beam . That help ?

Lost track of this one. My point about the instant is that your dropping down from a 22mm outlet from the UVC and then have the 15mm inlet / outlet of the instant. There will be a drop in performance there without a doubt, how much exactly will be down to the unit, but it is a definite design consideration. Also, I'd be VERY interested as to what the Steibel unit will produce as useful heat at anything over 10/12 litres per min with cold water going in. @JSHarris, can you add some details if possible please? Ta. In a nutshell yes. With a possible 12kw of direct electric heating ( 4 x 3kw immersions @ 2 per tank ) I seriously doubt you'll ever need a back up on the back up. By all means fit a cable for an electric instant, but I'd hold off buying and fitting one unless it's needed. Plumb both cylinder to the ASAP ( low grade heat to the TS and high grade heat to the UVC. UVC selected as manual boost only for when pv isn't generating ). It would be, imo, madness not to as you'll have oodles of DHW, a backup plan in case the ashp goes down / off for maintenance, and most of your DHW supplied at the better range of CoP from the ashp.

No refunds given ✌️️ Last time I 'sabotage edit' one of Peter's posts ? "If you can't do the time, don't do the crime"

Oh, and sorry @Dee. Another innocent thread hijacked and disgraced. Freedom of speech isn't all it cracked up to be

PS PMSL

Penis, I mean truce.

You may want to check your last post. I fear you may be stalking me especially on Thursday evenings in Merthyr where I dress up in ladies clothes and dance for 50p for the boys....

This board has some great features. You can select a little slider tick box on any thread. Where it says Submit reply just slide the 'notify me of replies' doo dah. To notify a member that you've mentioned them in a post just type @ then the member. A drop list will appear and you simply select them. Like this @Dee. It'll go blue when done correctly.

The door is open, he's has only to walk through. There are a few 'missing in action', a bit like yourself, but hopefully as time passes the repeat offenders will surface .

Dee, all you had to do was check a few phone boxes and you've have found our sordid website. Good to hear from you . He decided that this was a path he'd rather not tread I'm afraid. I believe you can find him on the GBF . I do miss the grumpy old git

Ian, your not the antichrist. Don't be so harsh on yourself eh? . PS ✌️️

Shows they work Better stuck to the magnet than inside the boiler

Let's answer the op then. If the 38mm battens are through fixed at regular intervals where the WC fixings reside, then I see no issue, but it is a lot to ask at such small points TBH. Adding a horizontal wall plate, as I've done with 7" timber in my pics, would straddle 3-4 of the 140mm frame studs and give you some serious rigidity. Show your plumber the pics and see if he is OK to cut sections of the counter battens out and fit a similar plate arrangement. For belt and braces I then fitted the 40x40mm UniStrut and punched timber locks through the UniStrut, wall plate, air tightness OSB layer and into the frame studs. To demonstrate how good these fixings were, I stood on the front edge of the extra long projecting WC pans, after mounting them to the frames temporarily through a disposable plywood baffle ( to represent the PB and tile layer ) and bounced up and down on them. You could park a car on them ( 3 X WC's on that same elavation ).

You've answered your own question then, no glue it is. . I'd also reconsider sheets of OSB instead of T&G if your remit is to be able to lift the floor for any reason. T&G is a right pita if you want to lift sections without damage.

Can't you simply replace the WBS+BB with an oil fired unit? Simple, cheap enough to run, and idiot proof ( if your making sure they don't run out of oil that is ). How would you integrate E7 / E10 other to provide heating ? Would you fit an electric boiler ?

I was lured here under the promise of free beer.