Browse Forums Renovation + Home Improvement 1 Oct 12, 2014 4:01 pm Hi all, I recently bought a house (approximately 70's - supposed Allworth home) and have been slowly doing it up, making small improvements (painting, plastering, electrical etc) Now I've come to the bathroom, which was not noted in building report as 'leaking' or 'rotten'... However I noted it and went along with the purchase. The slab is a suspended slab with the typical tin sheeting as part of the formwork. It rests on a short brick wall either side of the slab. Between the short brick wall supporting the slab, is a 100mm cavity, then the exterior brick wall. Now, where this cavity is, is a single hardwood bearer with the pine frame sitting on top. How that passed a building inspection is beyond me, as the bearer has to go a six metre span without any supporting posts in the middle. Due to a shower leak, the corner of the hardwood bearer on both walls has rotted away, leaving the frame free floating, with the weight of the roof pushing down on it. Now, my question; I've thought about this, coming up with two options. Each with their pros and cons. 1) Chip out the whole slab, and relay it properly, and let the timber frame sit on the slab. I'm also modifying the bathroom layout, moving toilet/bath positions so I could have a nice slab with plumbing already set in the formwork. I guess this option really gives me peace of mind and would be solid as. 2) Someone suggested lay concrete piers in between the cavity - or whatmore, fill the cavity with concrete all the way up, have a hob just over the existing slab for the frame to sit on. With option 2 I wonder about what effects it would have filling in a (useless) cavity. I don't know if it's there for a reason or just for the bathroom slab. And again with the piers, I would wonder if they would move around, seeing as though I could not dowel bar to the existing slab. This would also mean I have to drill new holes to move plumbing, and refill the holes where nothing would be. So, please lay your suggestions or advice down. Thanks for reading, Carl. Re: Subfloor bathroom slab questions 2Oct 12, 2014 4:21 pm My 1970's house has similar suspended slabs for the laundry and bathrooms and I also had a rotted bottom wall plate and termites due to the shower leaking. I successfully renovated all these areas without removing the slabs but I had underfloor access. I did have to remove all the internal wall linings to inspect and repair the termite damaged timber framing.
Question - Is there a crawl space under your suspended slab? (to allow access to the underfloor plumbing) If there is no access under your bathroom floor, then it would appear to be easier to remove the slab. This will allow access to repair/replace/re-support the bearer (the roof may need to be propped while this work is carried out). The new underfloor plumbing could then be installed. With reference to the bearer spanning 6 metres, the bearer may have intermediate supports on engaged brick piers or be dyna bolted to the external brick wall. Re: Subfloor bathroom slab questions 3Oct 12, 2014 5:35 pm Thanks for your reply! Yours could be similar. It's a South Penrith area old estate. Yes, there is crawl space under the slab. No problem there, but then you come face to face with the wall that the slab sits on, which is also where the plumbing runs (and leaks - damn yorkshire joints) but no, literally no easy way to access that plumbing. Because of the quality of the concrete existing (rather poor) I'm just wondering what option to go with. I can look through this cavity with the torch and see no mid point supports. It's my first home so I hope to do it right. Slab out is a little more work, but surely that'll all pay off at the end. Re: Subfloor bathroom slab questions 4Oct 12, 2014 5:51 pm I'd tend to go the whole hog, rip it out and re-new the slab in the bathroom. It also sounds like any termite proofing has been compromised as well in that area so I'd fix that at the same time. Good luck and keep us posted. Stewie Re: Subfloor bathroom slab questions 5Oct 12, 2014 6:31 pm Stewie D I'd tend to go the whole hog, rip it out and re-new the slab in the bathroom. It also sounds like any termite proofing has been compromised as well in that area so I'd fix that at the same time. Good luck and keep us posted. Stewie I'm inclined to agree with you, Stewie. Thanks. Most of the ant capping in that region is rusted too. Like I said, I'd rather do it properly - no bandaid situation that could cost more in the long run to rectify. I think I just needed extra opinions. Thankyou kindly. (any other advice or tips still welcome.) Jimbo73 I would use heaps of adhesive on each sheet and screw rather than nail. use as many as you like cheers Simeon 1 4064 XCEM Alpha flooring seems to relatively new and I could not found any reviews. Have you or someone you know have used it and would recommend over other subfloor options?… 2 7588 Would also like an opinion from anyone that has used xcem over hebel for floors. Thanks 1 14225 |