I am replacing carpet with laminate over the solid ground floor of my 1970s house. The floor is covered with what I understand to be thermoplastic tiles. They are black and 9” x 9” x ⅛”. The tiles are damaged around the edge where previous carpet fitters have nailed gripper rods through them, causing them to shatter. Can anyone advise of the purpose of the tiles? Are they intended to form a DPM or are they just for insulation? I cannot determine if there is any other form of DPM. Given that the tiles are cracked, they are not forming an effective DPM, though I have seen no evidence of rising damp. Do I need to replace them, or can I just use a waterproof laminate underlay? If I remove the damaged tiles, I’ll need to apply an alternative DPM and level the area. Can anyone advise of suitable materials or products? ARDITEX NA perhaps? It would be good to minimise tile removal as I’ve heard that tiles from this period may contain a small amount of asbestos. As another complication, a small section of the floor around the doorframe is raised up by about 8mm forming a step. It looks like it is a small section that has raised rather than the entire floor has sunk. I had planned to chip away at it then use a ready mix concrete repair until I realised the DPM was in question. The cause is a mystery but there is a heating pipe there. Surely the heat couldn’t cause this? Could a leak in that pipe cause swelling and result in a step? There’s no sign of moisture. Some pictures: http://www.geebs.plus.com/floor/DSC_4476-web.jpg http://www.geebs.plus.com/floor/DSC_4478-web.jpg http://www.geebs.plus.com/floor/DSC_4479-web.jpg http://www.geebs.plus.com/floor/DSC_4480-web.jpg I was comfortable with fitting the laminate but these problems are a bit much and I want them dealt with properly. I am thinking I just need to get a builder or floor specialist in. Any comments or pointers are welcome!
The tiles won't be acting as a dpm and your right, they may contain asbestos. I've seen old lead pipes do that to screed before ! If the house is seventies it should have a dpm as it was 1965 when it became mandatory.
It still might not have a DPM under the floor. Some houses in early 70s don't have a DPM as I've found out over the years. A estate near me started getting build early 60s and finished in 70s and no houses have one. If you take skirts off on the outside walls you might beable to see one at the edge. I way I do them type of floors is Remove tiles Remove adhesive Ardex na screed Ardex Dpm 1c Ardex NA screed again.
If the tiles are 9" then there is a high possibiltily that they do contain asbestos. The tiles would of been adhered using a bitumen based adhesive, this has been acting as your DPM. On removal of the tiles you will remove some of the bitumen so hence breaching your current working DPM. My advice is as above, but slightly different using different products. Ardex products are great but these will do the same job at a lower cost. Remove tiles Remove adhesive residue Bostik Screedmaster One Coat Membrane DPM (your substrate will be rough so your coverage will decrease and you will now tank your floor Neat Screedmaster Primer Screedmaster Flow smoothing compound
12 x 12 tiles could also contain asbestos as it wasn't banned until 1999. And bear in mind old stock may have been used after that year !!
The old floor tiles do contain a small amount of asbestos ( Marley tiles etc.) chrysotile (white) asbestos fibres. The bitumen adhesive also contained the same asbestos fibres. However the chance that the floor tiles or adhesive can release fibres and become respirable when disturbed is very low. To remove this type of asbestos containing floor tile, you do not need to be a licensed asbestos contractor and the works are NON Notifiable (14 days) however you do need to comply with the asbestos regulations 2012 to safely remove the tiles & bitumen. If you go on to the HSE Books web site ( type this into google) and then type in the search bar on HSE WEB SITE 'HSG 210' this is a book full of safe methods of work to remove asbestos containing materials such as floor tiles. If you can follow these methods and meet the HSE's minimum requirements then you should be able to proceed and remove the tiles without fear of exposure to asbestos fibres for yourself and those who occupy the area after you have finished. (Also eliminates potential prosecution etc.)
Taken from a chat I had with the owner of the only accredited material analysis lab for asbestos in Oxfordshire
Just remember if you start trying to remove the adhesive it could also have asbestos in...this will be worse in my opinion than uplifting the tiles
Thanks for your advice everyone. All very useful! Conflicting comments re existing DPM, but I appreciate it's hard to be sure in the circumstances. I have documents saying it was built in 1969 and others saying 1971. Written in pencil on a joist in the loft it says "This house was built in 1973". Most of the floor seems good, but at the moment I don't think I can rectify the problems properly myself so I'm looking for a contractor. If anyone wants to put any names in the hat I'm in Market Harborough (Leicestershire/Northamptonshire border).
Hi gaz, How did you go with this one in the end? The bitumen was definitely not the acting DPM but rather the adhesive used to stick the tiles to the floor. I am currently dealing with my 1950's house. I had a a sample taken from the tiles and adhesive; asbestos was found in both so I am having the lot removed. I will then go about levelling the floor, adding in a liquid DPM, more levelling compound and vinyl tiles as the finish.
Thanks merit - there are some of us still around! ; ) amazing how many people just can't be bothered; my philosophy is that these things have a habit of biting you on the backside if not done properly!
Just remember to use the right compounds and no primer below the sarnie and you should be golden, in ideal world grind the bitumen away then Dpm the subfloor then one coat of screed over top
I'm in agreement regarding no primer; the Ardex data sheets say as much. The plan is to get an concrete sub-floor so that things will adhere to it properly then to go with Arditex NA, then the DPM, and then finish off with another layer of Arditex NA. Regarding the bitumen it's a tricky one as there are 2 factors fighting against each other; firstly to get it the stuff off grinding is pretty much the only solution, however, one then has to deal with the risk of releasing the asbestos - in fact grinding is pretty much the worst thing one can do! In fact, this will be ok as I have an asbestos removal company coming in to carry out the work so the area will be 'closed down' and the men in white suits will carry out the work. As I understand it involves using extractors on the back of the grinding tools, an air circulation system to be used etc.. so fingers crossed will all be ok.
Only thing I'd say is in regards to the thermos and asbestos is its trace blue asbestos in them, you are kinda of going to the extreme in removing them, I've done the asbestos awareness course and in regards to thermos they are so low risk they in a domestic situation can be taken up yourself and just watered right down to stop fibres getting in air then vac area and not sweep, if you were doing 1500m2 in a school that's a different beast. Wet the floor and grind bitumen back then Dpm the subfloor then a coat of water based, plenty of us have done this method on the site.
I have been doing a bit more research on this project... Once the thermoplastic tiles and bitumen adhesive is removed the plan is now to go with: Karndean Art Select Sundown Oak Uzin 2000s pressure sensitive adhesive F ball Stopgap 300 F ball P131 Primer F ball F75 F ball 600 base Weak Primer (10 - 12:1) The kitchen units are coming out (convering 5m^2) and the total area to be screeded is 36m^2 with flooring finish to be on 31m^2 of that. I have read posts from mattysupra and dazlight on the diynot.com forum. I understand it is an acylic levelling compound that is required as the first coat. On this basis will it be ok to use Stopgap 600 base for this layer as it is water based? The 36m^2 is split with 11m^2 being in the new part of the house and with a DPM present. The remaining 25m^2 is in the old part without a DPM. I have had 3 companies to look at the floor (who supply and fit) and 2 of them used a damp meter measure with the readings being in the region of 3 - 4%. None of them gave me a figure for % RH. At present the floor is uncovered and so may not be giving a true reading; once the new floor is installed the figure may increase due to the current moisture being able to breathe. Whilst the figures are low I would have peace of mind to have a DPM and think it is wise to do so although it will naturally set me back a few quid extra. Other considerations are an inspection chamber in the new part of the house. The plan here is to go over with Ardex A45 and smooth over the edges to make good ready to accept further compounds. It will be sealed and covered as there is access elsewhere. Dazlight - you advised of 20 bags of Arditex NA self levelling via diynot.com. I have had another look at the floor and the new part (approx. 11m^2) appears to be roughly 15mm lower than the old part. There are also ups and downs in the old part. I am thinking I need to buy 25 bags of Stopgap 600 and 14 bags of Stopgap 300 for a total area of 40m^2. I hope this sounds reasonable?
I'd get a pro in, by sound of it you could latex that floor 3x with the amount of screed you intend buying and you can't prime under a dpm or dpm over a water based screed.
