Under Floor Insulation.

About: Just your average bloke in beautiful New Zealand, solving my seemingly unique problems because I cant find any one else that has.
A few years ago living in yet another freezing floor rental, i  found a way to change things with out to much expense.

Insulation works by trapping a layer of air, against a surface just as our clothes do on our skin, whether this is with in its folds or in a box..

What i used;
  • Polystrene boxes (Picture 1)(  I used 40cm  x   40cm    x  80cm ) with lids - (sourced from www.freecycle.org and a local green grocer)
  • Fencing wire 
  • Hand saw
  • Fencing staples
  • Fencing pliers
  • Head torch (and portable lighting if you have it)

Very helpful;
A chest cart - (picture 2) -( see my instructable  on the building of one)

Your lay on your chest on it and push with your boots on the soil.. Much easier then crawling over stuff.. 

Step 1: Preparation

  • Find the access under your house and survey the under floor lay out of your house -
  • You want to measure the total floor space so you can figure out how many boxes you need. ( Floor width / box widths & Floor length /  box lengths)

  • Estimating the position of the boxes (long wise) and attached strapping with a fencing staple to the foundation wall floor bearer, knocking it flat after.  (picture 3)
  • Then drive in a staple in on the corresponding side
  • Thread the fencing wire through the far staple and lay out to the other side in preparation for fixing
  • Place the staple for the opposite side and drive halve way
  • If you have the lids, cut them to fit into the base of the box, holding and off cuts for stuffing spaces 
  • Place the boxes in the first row out in their approximate positions on the ground over the wire you layed out- so you can estimate which need to be cut to accept the floor bearers and any utility pipes.(DONT cut yet)

Step 2: Placement

Push the boxes up in to position fixing them in place by pushing the next box in tightly beside.(Picture 4)

 Cut the slots for the bearers ( for the box that fits over)  tight - so that when the box is placed it holds the others in place.

Same goes for any that are placed over utility pipes.(Picture 4)

At the end of the row, thread the wire through the staple, pull tight with the fencing pliers and fasten the staple off. (Picture 4)


a layer of reflective paper underneath would be even better.. although the whole idea is to keep the price down..



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    7 years ago on Introduction

    good idea if you have a source of styro boxes