Cheap and easy way to insulate underfloor of weatherboard house

[TimD]

Hi,

   I have an old weatherboard house and would like to get under the house and install insulation under the floor.

I have very little headroom (less than 1m) under the house so I think struggling with stiff boards is not an option. 

So I am looking for a simple and cheap method to do this. It does not have to be super insulation - just enough to take the edge off somewhat and something I can buy in-store. 

Also, hints on what tools I would need would be greatly appreciated too,

Many Thanks

[MitchellMc]

Hi @TimD,

What type of internal flooring do you have? Knowing this will help our members determine what type of underfloor insulation will help take the edge off and allow them to offer some great solutions.

It sounds like you have a very similar situation to mine as there is not much headroom to work in either. I have old timber floorboards, and the gaps in them allow the ambient air to flow through into the house. In my case, GI Building Sciences 1.35m x 22.5m x 4mm Reflecta Cell Floor Insulation or Ametalin 500mm x 60m ThermalFloor Reflective Underfloor Insulation would be effective as it would block that airflow. However, if your floor structure is conducting the cold and heat through it, then Bradford R2.5 1160 x 415 x 90mm 4.2m2 Optimo Underfloor Insulation - 8 Pieces might be a more viable solution.

I'll be keen to hear what type of floors you have. I might join you on this project as I'm not looking forward to the cold temperatures that we'll see shortly.

Mitchell

[TimD]

Hi Mitchell,

   Thanks for the quick reply.  Sorry I should have said...

It is old timber flooring and similar to your situation by the sound of it. They sit less than 1m above the ground, ie there is nothing between the floorboards and the bare earth. There are small gaps between the boards which do let the cold breeze in also.

The Reflecta cell floor and Ametalin look like the kind of thing I would be interested in however they appear to be special order only. If I went for this solution, I'm guessing I would also need to purchase a staple gun? I assume an office stationery staple gun would not do the trick and would need to be more heavy duty for the joists?

Thanks - any further recommendations from you or the community would be most welcome.

[MitchellMc]

These products are available through our Special Orders, and I would be happy to assist you with the ordering process @TimD.

I would suggest using an Arrow T50 Heavy Duty Staple Gun as lighter-duty units will have difficulty penetrating the hardwood joists. I recently used a budget-friendly staple gun to fix into softwood, which caused plenty of frustration, so I would advise using a premium product instead.

You might be interested in reading through these previous discussions: Insulating an old house on a budget by @JDE and Underfloor insulation by @Diannelin.

You should find these step-by-step guides useful: How to install underfloor insulation batts and How to install underfloor foil insulation. You'll be positioning your insulation from underneath, but there is still plenty of helpful information within them.

Mitchell

[JDE]

TimD

We recently did this. Yes it definitely had an effect. Not as much as doing the ceiling. As Mitchell said watch some of the bunnings videos https://www.bunnings.com.au/our-range/brands/e/earthwool. I was on similar height restrictions. Just some things we found.

Make sure you wear long sleaves , gloves- long ones and a face mask/ goggles (safety glasses didnt cut it) you will be laying up close and under the bats. If you do get the itch cold shower first not hot you dont want to open pores any more than necessary

Unless you are particularly strong in hand I suggest an electric stapler we bought a ryobi one stapler excellent - you will be putting in hundreds of staples.

Knee pads were great the builder left me lots of rubble

A good flood light and a decent pair of large scissors 

Floor insulation is different to ceiling bats they are stiffer to reduce sag and some have a membrane on one side (we used this and got it from Bunnings) 

Make sure you use plenty of strapping as it will ensure less sagging as bats swell

Dont forget insulation comes in different widths so make sure you get the right one to reduce wastage.

Not a fun job but in our case definitely helped

JDE

[tibz_timber]

Hi @JDE 

Were your floor joist hardwood or treated pine?  Interested in knowing how the Ryobi stapler handles hardwood.

Tibz

[TimD]

Thanks @JDE for the tips.

   I have just ordered the GI Building Sciences 1.35m x 22.5m x 4mm Reflecta Cell Floor Insulation (thanks for the tips @MitchellMc )

JDE, yes i was thinking I would just buy the Arrow stapler. I did consider the Ryobi to add to my "collection" but I am not sure I would get much use out of it after this job. I may yes still change my mind. With the Ryobi, do you just buy ordinary T50 staples like these Arrow? https://www.bunnings.com.au/arrow-8mm-t50-staples-1250-pack_p5911777 I am thinking as the Reflecta cell is only 4mm thick I probably only need the 8mm staples. The joists are 100 years old and rock hard, so I don't want too long staples to drive in I would think. 

[MitchellMc]

Hi @TimD,

The Ryobi 18V ONE+ Cordless Stapler is designed to be used with T-50 Staples, which have a staple size of 10 mm (3/8”) and a length of 6 mm - 14 mm (1/4” - 9/16”). The Arrow 8mm T50 Staples would be suitable for use in this tool.

Mitchell

[JDE]

Tim

The ryobi uses standard staples I ended up buying Ithink they were craft light ones from Bunnings. Sorry my wife has pinched it as she uses it when upholstering chairs etc. We used 8mm stapes from memory and yes it was into 50 year old cyprus worked well if you turned it up (it has adjustable drive) and held it tight against timber

JDE

[tibz_timber]

@JDE 

Was asking as my Ryobi 18GA brad nailer struggles with Australian hardwoods?  Yes, it will handle hardwood if it is clean and properly adjusted for a couple of hundred nails but then it needs maintenance and adjustment again.  Can get a little frustrating at times.  Just hoping the stapler was less temperamental.

Tibz