Reply With QuoteWell ,watch wise ,definitely a G shock.
I'd appreciate the creative thoughts of the handier members on this one.
Castle Draft is a period Maltese townhouse. The typical floor construction is unlike anything seen in Britain- heavy wooden beams spanning the rooms at around 3-4 feet centres overlaid with limestone slabs around 3 inches thick. On top of that goes several inches of fine limestone chippings which spread the load and finally the tiled finish typically laid in a dry screed.
I have a large ornate carved limestone ceiling rose which I need to fit in my dining room- around 20 inches diameter and probably weighing around 50-60 pounds.
I will be hanging a large and heavy chandelier for which I will make provision in the form of a hefty rawlbolt with eye fixing, and running the wiring in a conduit in the joint between two ceiling slabs. That is the easy part. I'm scratching my head over how to fix the rose.
I'm definitely going to use a strong mortar mix (we use powdered limestone instead of sand) and the whole affair will be neatly pointed-in as the finished ceiling is bare stone, the only finish being a couple of coats of linseed oil to seal the stone and bring out the colour.
But I will also need some fixings and here is where I could do with some suggestions. I can drill through the rose and countersink for hefty screws or bolts and can easily dress over the heads afterwards with limestone dust and cement. By the way the ceiling is 15-16 feet high so I will be working from my scaffolding tower and will temporarily screw a couple of battens into the beams either side and cut to length some loose battens to sit between them and hold the rose in place until it is fixed.
Will I get away with rawlplugs and large woodscrews or is there a better fixing? I'm wondering about lengths of female threaded tube epoxied into holes drilled in the ceiling slabs.
Thoughts would be welcome!
Well ,watch wise ,definitely a G shock.
Addendum: the obvious thing would have been to access from above, but unfortunately it isn't possible in this case. The dining room is on the top floor of the house. Above is the flat roof which was redone a couple of years ago- above the layer of chippings is a damp proof plastic membrane, then 2 inches of polystyrene insulation and then a 2-3 inch concrete screed. I can't cut a hole in that lot as it will compromise the waterproofing. I had planned to hang the chandelier from a steel bar and hanger plates on the beams until my stonemason turned up one day a few months ago with the beautiful stone rose he had carved... so it has to be fixed from below.
I'd be inclined to use rawlbolts or anchor bolts rather than plugs and a mortar layer between the rose and slabs.
We regularly underestimate the load carrying capacity of steel though, this is held up using one m5 bolt and probably weighs around 20kg.
Please, please don't use woodscrews in rawlplugs. They don't spread the load evenly through the plug, tending to concentrate it at the bottom end. Concentrated loads are a recipe for failure.Originally Posted by draftsmann
Faced with this (the 90cm plaster rose and chandelier were both new) we called in a professional. He literally spent all day with an extra piece of joist, bolts, special screws, special mortar and all sorts. I'm reasonably handy and have put up lights and roses before but I just left him to it tbh. It's lasted 4 years so far, cost about £300 for his work I think (and he was here for about 10 hours).
I'd look at using a number of sleeve anchors instead of screws & plugs. This sort of thing:
http://www.screwfix.com/c/screws-nai...ory=cat7290066
They come in various lengths depending on the thickness of the item to be fixed (the rose). One issue might be how to hide the head in the rose as you need to be able to get a spanner on them to tighten them up.
Resin fixing would be an alternative. This page has a selection of resins (some of them suitable for overhead installation) & associated threaded rod:
http://www.screwfix.com/c/screws-nai...&page_size=100
Mind you, you will have the same issue of how to hide the rod & nut so you might as well use the sleeve anchor. I realise you are in Malta so Screwfix may not be round the corner but it shows the various items.
I have two of those in my London apartment, thankfully I have a loft with easy access and it was straightforward to fit noggins between the joists to get a secure fixing into from above. Unfortunately that solution won't work for me in Malta due to the floor construction.Faced with this (the 90cm plaster rose and chandelier were both new) we called in a professional. He literally spent all day with an extra piece of joist, bolts, special screws, special mortar and all sorts. I'm reasonably handy and have put up lights and roses before but I just left him to it tbh. It's lasted 4 years so far, cost about £300 for his work I think (and he was here for about 10 hours).
You've identified the problem I've been struggling with- deploying a spanner to tighten a nut below the surface of the stone rose. I divide time between Malta and Britain so sourcing materials that I can't find on the rock is easy enough.
Understood. Equally I'm concerned about any expanding kind of fixing splitting the soft limestone if I'm not careful. Overtightening could be a disaster.
If I could find some female threaded tube that I could epoxy into the roof slabs I could then use countersunk pozi machine screws, I'm coming to the conclusion that might be the best solution. Any suggestions where I might find suitable tube?
True, I don't envy you the job, although the house sounds nice :). I guess I was just saying personally I'd bottle it, but good luck to you if you take it on yourself.
https://www.orbitalfasteners.co.uk/e...xoCOFoQAvD_BwE
Looks like they were made for your job.
Better sizes than M6 available too.
https://www.orbitalfasteners.co.uk/en/categories/rawl-rawlplug-internally-threaded-resin-sockets
Last edited by JasonM; 12th August 2017 at 17:10.
Jason thank you. I don't need a pack of 100 but after a quick search of Amazon and eBay I found and ordered this - eleven quid and job done: http://www.ebay.co.uk/itm/Rawl-Inter...72.m2749.l2649
Good o, I would have been tempted to go a bit thicker myself, I have no experience of this sort of thing but I tend to go for overkill.
Four of them and it won't be going anywhere, especially with the mortar bond to the roof slabs, it will do the job perfectly.Good o, I would have been tempted to go a bit thicker myself, I have no experience of this sort of thing but I tend to go for overkill.
Lets hope it doesn't fall on anybody's head.
Probably best to get the Trotters to do it
To be safe, I'd better not invite you to dinner Aeschylus.
:) It just sounds like a very heavy thing to fix to a ceiling that doesn't really lend itself to stuff being fixed to it.
Threaded inserts would also be ideal.
http://www.screwfix.com/p/insert-nut...FSgy0wodgTwH1A
Would they work in soft stone?
If its a delicate limestone I'd use a liquid saturate stabiliser to keep it sound.
I'm thinking about amending the scheme slightly and using expanding foam to bond the rose instead of mortar, as well as the epoxied threaded inserts and machine screws I ordered. The ceiling slabs aren't perfectly flat or level but i can support the rose on temporary battens between the beams while the foam is curing and that way I should get a very permanent and perfectly level fixing, just leaving the edges to point in when it's in place.
Not needed on indoor stonework. For internal and external stonework we tend to use 2-3 coats of linseed oil to seal and stabilise. The nature of limestone construction is that anything exposed (like parapet walls) is regarded as sacrificial, with a maximum 50-60 year life.
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