Browse Forums Flooring & Floor Covering 1 Jul 26, 2009 9:36 pm Just put in some underfloor insulation (expol polystyrene sheets) in our 10 year old house (Melbourne), under tassie oak floorboards. It has been in a couple of weeks and we have noticed big gaps appearing between floorboards since putting it in. Nails are also starting to be pushed up and there are many more creaks and "cracking" when walking around on the floor. I'm assuming the added insulation is drying out the floorboards (which are in a north facing room and being winter, getting full sun for most of the day), causing the wood to shrink. The biggest gaps are probably about 4mm. Has anyone else had this problem? Any suggestions on how to prevent this from getting any worse? For that matter, I wonder how much worse it will get?? The resulting insulation is fantastic, but didn't really expect the cosmetic effects! We wanted to do the rest of the downstairs area but not sure about that now... Re: Underfloor insulation and gaps appearing in floorboards. 2Jul 26, 2009 10:23 pm Unfortunately there is nothing you can do to stop the natural expansion and contraction of floorboards. I imagine the under floor insulation has stopping the transferance of moisture from under the house to the timber. Are the floor boards directly over the joists? If so it is unusual for a house not that old. Re: Underfloor insulation and gaps appearing in floorboards. 3Jul 27, 2009 8:36 am Yes, surprised us too! And yes, the floorboards are directly over the joists. If we at some stage put a floating floor to cover the real floorboards, is the same thing likely to happen? Re: Underfloor insulation and gaps appearing in floorboards. 4Jul 27, 2009 12:09 pm Its hard to say. Acclimatise the boards in the house for a fortnight. I would put them down in winter when the air is drier. You would lay the boards perpendicular to the existing ones. It would be a shame to cover up real timber wiith laminate flooring IMO. Floorboards are much better when laid over particle board flooring when going over joists. In the days gone, timber flooring was laid directly over joists as the boards were intended to be covered and not the actual feature flooring we use them for today. IMO its very 'cheap' for a builder to lay timber flooring straight over joists. Re: Underfloor insulation and gaps appearing in floorboards. 5Jul 27, 2009 3:06 pm Thanks for your prompt replies – your advice is much appreciated. You have just reinforced something we keep coming up against in this house. I think the previous owners were on a pretty tight budget when they built the house (we’ve been in for 3.5 years). This is starting to become apparent in not only the internal fittings but the basic foundations of the house such as the flooring as you mentioned being cheaper to lay directly on joists rather than using particle board flooring underneath. BTW would this also add to the “springiness” of the floor? We find that there is quite a bit of give in the floor (ie. you can hear the wine glasses in the cabinet, TV wobbles etc. as you walk past!). Or does this have to do with the support under the house? Is this something that can be fixed? Re: Underfloor insulation and gaps appearing in floorboards. 6Jul 27, 2009 3:34 pm Definately, I had a house in Sydney with Cypress pine floorboards laid directly over joists and it 'definately had more spring compared with boards laid over PB flooring. Not to mention colder as well! Re: Underfloor insulation and gaps appearing in floorboards. 7Aug 23, 2009 10:01 am How moist is it under the house? I've recently insulated under my pine over joists floors, (poly batts) and has a water based poly finish and not experienced any of those issues. Part of my water based poly choice was to avoid edge bonding which might be helpng by allow a bit more moisture balance throughout the boards and allowing them to expand and contract properly But I do not have sun landing directly on the boards which I suspect is your biggest issue. It is very dry under my house. ie no hint of moisture in smell or touch at any time throughout the year. As for the floor moving and cupboards rattling - I don't have any of those issue either in this place - so perhaps it's just this house. Re: Underfloor insulation and gaps appearing in floorboards. 8Sep 03, 2009 10:25 pm Not moist under the house at all. Yes, I think the problem is more from the direct sun hitting the boards and having nowhere to escape to. It’ll be interesting to see what happens over the “real” heat of summer. But then again, the area which the sun hits in summer is so much smaller. I was beginning to doubt that the insulation made much difference at all (especially considering the huge gas bill we still managed to get!), until visiting a friend’s house with no insulation. My feet were absolutely freezing! We’ll just have to live with the gaps I suspect. Re: Underfloor insulation and gaps appearing in floorboards. 9Sep 04, 2009 7:22 pm The gaps you get in front of a fireplace are the worst Thankyou for your advice. We do have Caesar coming out and hopefully resolve the issue for us. 4 18707 1 10115 4 6006 |