Home DIY

Some building control depts. have allowed loft conversions under a certain size to have an upgraded alarm system fitted in lieu of rated fire doors. I think this is what the architect is getting at. It would all be agreed by BC at the design stage anyway.

Whether this is likely to change in view of recent events I dunno, but the local BC office should be able to confirm.

I've just dismantled the floor in a corner of our bathroom. The idiots who installed it (before we moved in) had tried to create a wetroom by tiling straight onto the plywood floor without sufficient tanking or extra noggins to stop the floor flexing. Inevitably the ply rotted out and I'm now letting the joists underneath dry out and treating the mould on them.

I'm planning on putting down some 18mm marine ply and installing a proper shower cubicle. Annoyingly, to get the slope on the "wetroom" floor the installers skimmed some wood off the top of the joists, which means that I need to create a properly level and rigid floor structure to fit the ply down to. I don't think I can accurately create a level structure by flatteing the joists and screwing extra wood to the top of them and I don't want to take more material off the existing joists in any case.

My instinct is to go all out and sister the affected length of each joist (about 1.2m) with the same type of timber (roughly 165 x 45mm). At one end these would rest on the top of the wall of the room underneath (which would bring them up neatly to the correct height) and would be bolted to the existing joists with m10 coach bolts and timber connectors. I'll also add noggins to support all the edges of the new ply. Is that massive overkill? Is there a simpler way to create a solid level structure to put the ply onto?

Need (want) to strip a flaky-old-paint wall back to red brick.

Can anyone recommend the best angle grinder attachment for doing so? Im assuming wire wheel of some sort but confused about all the different shapes/types of wire.

It's a popular way of doing it. Just be careful that you don't weaken the existing joists when you drill them for the bolts. Not sure whether the noggins are going to do too much.

Can of worms. Assuming its exterior you could try jet washing first and then a chemical poultice. Not sure I would recommend an angle grinder at all. A lot depends on the type of red brick though.

Thanks @Airhead, the regulations for drilling holes in joists are quite restrictive (between 25% and 40% of the way along the beam, on the centreline only) but I don't see how you can adhere to them when sistering, since you need to add bolts wherever the new joist goes and best practice seems to be to stagger them 1/3 up, 1/3 down at roughly 20cm spacing. My interpretation is that any weakening of the existing joist is compensated for by the presence of the new one, plus the holes are tiny (10mm) compared to the depth of the joists. The joists seem to be quite over-specced anyway, since they're at 30cm spacing.

Interior wall. Other than being time consuming and dusty, any particular reason why you would you not recommend angle grinder?

Dust would be a big concern. Damage to the brick surface would be a worry too, depends on the brick type and condition though as I mentioned before. Type and condition of bricks and paint would also dictate which kind of wire wheel design would be most effective.

It's not a job I've had to do much, I'd probably try an IR stripper to see if it works.

Maybe bolted complimented with screws. As long as you don't go crazy with the number of bolts or the size of them you should be fine. I've had to replace a broken joist following a friends diy efforts before but he was reckless and didn't listen to warnings.

If it's old paint, assume lead is present and follow HSE recommendations.

http://www.hse.gov.uk/pubns/cis79.pdf

Cheers for the comments re: the fire doors/alarms. I'm not convinced that the architect is 100% on this so I guess it will be a matter of the building controls guy.

Can't say I'm particularly keen on replacing all the doors in my flat, they're nothing special but all reasonably nice condition Edwardian pine doors.

It is a fairly small loft conversion (plans attached) so maybe that will be the way to go.

3 Attachments

Analog plans, very hipster. :)

Might toolstation item50096,
https://www.toolstation.com/shop/Construction+Materials/d210/Builders+Metalwork/sd2797/Heavy+Duty+Strap+Flat/p50096
and ts32159
https://www.toolstation.com/shop/Ironmongery/d170/Metal+Edging/sd3009/Checker+Plate+Metal+Sheet/p32159
be of assistance?

Yet to delve through the garage for the pot(s) of liquid self-levelling quick cure resin for you.

Old school, eh. and by the look of it you have originals? bit odd

Done a small test patch on the area with combination of worst looking brick/most adhered paint with a small wire brush on drill. Came of pretty easily and bricks looks ok - assuming all the small bits left in the mortar will take at least as long to clear afterwards.

The room is completely unfinished and I can seal it + have decent PPE so going to order a few diff. types of wire brushes and have a crack at it next week after drywall and before paint.

Be interesting to see the results. I've never had to do that job but it would be good to learn from your experience.

@ffm yes over specced but what you loose on materials you will gain on time and ability to give you a level job if someone has been hacking the joist about. On where to bolt who says centreline of joist probably an armchair engineer. Have you thought how you will drill the holes? 300mm minus 45 mm does not leave a lot of space.

That's a scan of the originals that he sent me. I thought an artisan architect would be more keeping in style with the area's gentrification.

One of these will aid access;
https://www.amazon.co.uk/Milwaukee-M12BDDXKIT-202C-Driver-batteries-charger/dp/B00NMLPW20/ref=sr_1_1?s=diy&ie=UTF8&qid=1505999471&sr=1-1&keywords=milwaukee+12v+drill+kit

Anyone know where I can find food-safe paint? Picked up an old kitchen balance scale on the weekend. The bowl you put whatever-it-is-you're-weighing into had been painted over the original (chipped) enamel. The paint was all flaky so I've taken the paint off and polished off a bit of rust so it could do with a fresh coat of something.

When I said over-specced I was referring to the existing joists, since the span is only about 2m. My point was that I'm not concerned about the material that's been skimmed off them. I probably could level it up just by screwing 3x2 onto the side of them but I agree with you: if something's worth doing, it's worth overdoing. Plus using 7x2 means that I can rest them on the bearer at one end and they'll be automatically at the right height.

The restriction for drilling holes only on the centreline is actually from building control, but I think that really applies to holes for pipes or cables. If you're filling the hole with a coach bolt then it will be just as strong under compression and the sister joist should add tensile strength and therefore rigidity.

Access will be tight, but @mespilus has kindly lent me an angle drill that will take care of it and happily I have a 10mm wood bit that is just longer than the width of two joists.

Yeah the building control guidance relates to Plumbers and electricians who have a habit of cutting big chunks out of joists.
I would think on getting the drill in you've got 300mm minus the joist 250 mm minus the chuck 190mm minus what ever the right angle attachment is leaves you not a lot to get through the 100mm of the two joists plus you will have no space to give the drill some wellie to get through the joists so each hole will take a while. But if you are putting noggins in do you really need to bolt the joists together?
If you need it I have specialist angle drill somewhere you can borrow.

So I've just stripped some wallpaper in my sisters new pad and it was put up over fresh plaster.

Will I need to do a mist coat? It's not fresh plaster but unpainted all the same

Will this work to replace a 2 wire standard light switch?

https://www.oceanlighting.co.uk/lighting-controls-c282/ocean-owpir360-occupancy-sensor-pir-motion-sensor-p24441/s25956?gclid=EAIaIQobChMIqL6n847A1gIVDrcbCh0B1A7UEAkYCSABEgIi4PD_BwE

As long as there's only one light switch for that circuit... yes.