How to re-level ground floor of cement stump house?

Question

Current house has cement stumps. Wanting to install engineered flooring downstairs. Some parts are almost 40mm out, unable to do jack and pack because upstairs (added in 2006) is dead level. Could you suggest what could be done before laying down engineered flooring, to level downstairs? Currently it has timber floorboards.

JacobZ · Answer

Hi @daniel_leong,

As long as the floorboards are still solid and intact, then you should be able to reuse them, but it all depends on how much damage there is because ultimately, removing them will almost certainly cause some.

So, best case scenario, you don't need to use yellow tongue, but I would budget for and be prepared to use it if the need arises.

Jacob

daniel_leong · Answer

Thanks @JacobZ for your reply. Sounds like we would need to remove the existing floorboards in the areas that are 40mm out, most areas are <10mm so a levelling compound could be used there. After we remove the existing floorboards, do we put it back in or use yellow tongue? Thanks again!

JacobZ · Answer

Hi @daniel_leong,

If jacking and packing the floor from underneath isn't an option, then I think the best approach would be to remove the existing floorboards and level things at the joists. You could do this by cutting tapered timber packers or "slivers" to suit the amount of correction required and fixing them along the tops of the joists. This would give you a level surface to reinstall the subfloor onto without affecting the level of the floor above.

Another option would be the Dunlop Timber Floor Level Flex Kit. This product is specifically designed for levelling timber floors. It can be applied from a feather edge up to 12mm normally, while areas between 12mm and 30mm can be built up by adding suitable 2–5mm aggregate as specified in the instructions.

Dunlop also recommends that, when levelling an uneven timber floor in this manner, 6–12mm plywood or fibre-cement sheeting is screwed or nailed over the leveller afterwards to create a sound, stable base. Your engineered flooring could then be installed over this substrate in accordance with the flooring manufacturer's installation instructions.

The limitation is that the Dunlop system only allows you to build up to 30mm, so if the variation in the floor is substantially greater than this, while a fair bit of work would be involved, removing the floorboards and levelling at the joists is likely to be the more practical solution.

Let me know what you think.

Jacob