Dee J

Just a point to ponder... Many commercial buildings I visit have exposed blockwork walls inside (gyms, galleries, studios etc). Either painted or some nicer facing blockwork. Often these have flush electrical accessories. So the electrical services must either be a)on the other face of the wall, b)between the skins of a cavity wall c)threaded up through hollow blocks or d)the 'exposed blockwork' is actually a fake cladding. Anybody got any experience of this... (c) especially? Where there is no clear delineation of wall construction/first fix... do the block layers thread flexi conduit in as they go? And how common are hollow blocks in this sort of setting? And are they often infilled afterwards? Thanks.

Full height wall both sides of the stairs? Prefabricated staircase or in situ build? Cant see that you'd manage to slot a prefabricated staircase between two plasterboard walls without damage....

Tend to find with these domestic systems that once you exceed a handful of units the incidence of problems, mis triggering, low batteries and similar tend to become really a nuisance. I wonder if a commercial system, with centralised battery and control might not be a better option.

I think if you're making anything big enough to act as a useful cupboard, that will challenge the wall structure considerably. It's almost like creating a doorway. And given the lack of foundations in these old structures, how the transferred load acts is difficult to predict. On a smaller scale, creating a tiny alcove in our rubble stone house produced an egg-timer effect which seemed like that the entire house would fall out of the tiny hole! Interesting challenge to work with these old structures!

Anybody understand part K enough to say if there is a required thickness of handrail for a domestic building? Background...Trying to finish off our existing house prior to the hoped new-build. We've got a narrow staircase in a part of the building not yet signed off by bc. We've never had a handrail fitted. It's only eleven risers, with the first six treads forming a 180 degree turn. Looking to fit the minimum required handrail around the outer side of the curve. Also, as far as I can interpret, the first two steps need no rail. The only dimensioned diagram 1.13 seems to reference para 1.36 for non domestic. Why am I questioning this? It would fit the look of the stairs better to have a skinny 25mm metal rail than the usually supplied thicker ones. Do you think this will cause problems? Thanks Dee

Mention of second floor? So, ground, first and second? Do fire regs require some sort of protection of the stairs area/ escape route? Maybe precludes the full open plan option.

I do wonder about concrete finishes. If I look at the floor in the local B&Q, or in many exhibition centres, it appears to be a smooth satin concrete. Is that power-floated, polished or what? If I put a finish like that in my house (as part of the slab), what care and maintenance does it need? In the commercial setting it seems to cope with high stresses with little impairment. Thanks.

A great case of 'you can't get there from here'. To maintain the envelope and avoid a lot of the cold bridging, shouldn't the facia and soffit areas have been insulated... so as to maintain the warm roof skin, rather than reverting to cold roof internal insulation in those areas. But on the basis of 'we are where we are' the key detail will be the right membranes and sealing to try to limit condensation in that soffit box.

Fair enough. Probably not enough resistive loss to worry about. 10percent of not much is not enough to worry about. But I still don't have any problems with the various 240v led lamps I get from the wholesalers though. Used loads of GU10, ES and bayonet lamps with no ill effects. The only noise issue I have is a cheapy 12v switcher psu driving some resistor limited led tapes.

But..... that's just a 12v constant voltage supply isn't it.... the mr16 lamp still contains either an energy wasting linear regulator or a potentially noisy switching regulator. I'd understand the point more if you were using good quality constant current drivers driving unregulated leds... but of course you'd need a constant current driver for each group or set of leds, and you'd still be switching the 240vac at the lightswitch...

But what sort of regulator/driver do you use for 12v leds. Linear or resistive and you'll loose more energy in the regulator than you use in the led. And if you use switched mode you'll still run the risk of radio interference from poorly designed items.

What are the woes of mains powered led lighting? I get an LED lamp or fixture and plug it in... it works. Other than in some areas of bathrooms and swimming pools I've never understood the point of 12v lighting. And unless you run a lot of wasteful resistive droppers or linear regulators you'll still need the switch mode drivers similar to the mains based drivers....

How about this http://www.concrete-beton.com/en/wall-panels-concrete-panbeton Dee

Sounds like precast panels applied as a cladding might work. A quick google suggests such things are available.

Other than being a messy job with a tatty sideways socket theres probably not a lot wrong with it. If there's significant steam and grease exiting the hood then you'll have other problems beyond the socket. But you could always fit a short piece of ducting past the socket if it worries you.

That looks like a nice piece of kit. Single module double pole rcbos like this are fairly standard in France , but rarely seen in the UK. What's your preferred source for these parts? And how do you get round the various regs glitches when fitting them into pre-existing consumer units from other manufacturers? Such as approvals of boxes only apply when fitted with the box suppliers own components (especially when connected to the DNO supply direct) or the updated requirements on non-combustible enclosures? No criticism intended, just need to know how to present an install like this to my scheme assessor.

It's not ideal, but it's not terrible. Generally done for a single light fitting such as a porch or cupboard or for a small extension such as a conservatory. It would be unusual to plan for a significant part of the main installation to be configured in that way. But re-wires are often compromises if some parts of the house structure are inaccessible due to laminate flooring or other permanent finishes. I'd normally expect to discuss potential issues like this with clients at the planning stage ... so design decisions are are jointly planned. What does your electrician say?

You could finish the outer block skin one block lower than the inner block skin. Then the floor joists could safely jetty out as far as you want. Just carry the first floor cladding down low enough to cover the gap and ensure the insulation carries on up from the block wall to the timber frame.

For a shed? I'd use it without question. Cant see any aspect of the sealing or draining that would be problematic. But... was it scrap in the skip, or just placed there for a moment? Is it yours? Moral rather than architectural questions apply.

Galvanized is great, love the industrial look. Painted will quickly look terrible unless you get some high spec marine coating professionally applied. How about stainless steel? Box, iIbeam and PFC available. Or even engineered timber?

What's generally required is an electrical installation certificate (dead tests only). Having your electrician on site eases the path too. Make sure bonding is in place for a full domestic install. Or that TT earthing has been set up for site supplies.

That would fit the bill, but by the look of the TV example it looked to be standard block-on-its-side sizing rather than the longer Marmox format. I'll keep Marmox in mind for our project though...

The perils of lunchtime daytime tv. Looking at the build method of a bungalow shown partly completed on TV. Newbuild solid single skin blockwork structure due to be externally insulated and rendered - but it didn't look like passive slab base. From visible details it looked like strip foundation with a conventional screeded floor ( might have been slab or beam and block under). By the look of it there are a couple of courses of a different blockwork at the ground transition - some sort of thermal blockwork maybe to offset heat loss at foundation. Standard thermalite? or is there some wonder-product block with better characteristics?

Oh. Liking the look of that. Have you got a build blog or earlier postings of the build?

We took the unheated, high light level, high solar gain, high heat loss route on the sun-room of our current ancient house. Unframed 10mm single-glazed office partition glass 2.5 m high and 5.4 m long (6x0.9mm panels with silicone joins). Excellent system... a bright warm room when ever there is the slightest hint of sunshine. Open the doors and window to the house when heat transfer is needed. Open the skylights to ditch excess heat. Close it all up when it's dark or cold. Wish we'd built it earlier, and its one thing that we are afraid we'll miss in our new-build.