I have more of a question about cellulose insulation. I have a 100 year old Victorian farm house. Most of the walls are plaster with the narrow slats to support it. You can look all the way from the attic to the root cellar and there is a gap of about 1 foot around the chimneys. Can cellulose insulation help? We have already added siding woth foam panels and storm windows, but the house is still pretty drafty. I know there were other types of foam insulation that developed problems over time and wondered about cellulose. I also wondered about flammibility. Any info would help. Thanks
In an old house, I recommend attacking air leaks first: caulk windows, weatherstrip doors, repair windows so they are tight, etc. Often the local utility company will come and take infra-red readings on your house to help identify where heat is lost, and drafts enter.
Second, I recommend getting as much insulation in the attic floor as possible.
Often these steps make an enormous difference, and often are enough.
Then if you have time, money and patience, insulate the walls, but the best way to do it is either remove the siding and shetahing and install it from the outside, or remove the interior finish (probably plaster) and do it from the inside. Both are labor-intensive and costly.
But what I'm saying is, deal with everything else first and see where you end up, and do the walls last or never.
One problem with blowing cellulose insulation into the walls, well, two problems: it often settles, leaving the tops of the walls uninsulated, and also there is no vapor retarder, therefore the insulation can absorb moisture and lose much of its insulating value when wet.
Architect (NY) and Home Designer (PA)
Posts: 2870 | Location: Tobyhanna, PA | Registered: 24 October 2005
I have a related question. I have a 100 year old house and would like to use blown in cellulose insulation in the walls. The wall gap is clear down to the floor, but it is only 2 1/4 inch wide, and one contractor said it would not work, while another says he has done similar houses. Will it work. Thanks.
The main issue with retrofitting walls with insulation is the fact that you are introducing a condensation potential.
Without insulation, two things are preventing moisture that enters your walls from condensing: 1. Interior heat is warming the exterior cladding / sheathing. 2. Air circulation is exhausting the moisture to the outdoors faster than it can accumulate.
Introducing cellulose into the walls will 1. block enough heat from reaching the exterior cladding / sheathing such that it can now act as a condensation plane, and 2. reduce the air circulation, allowing condensation to accumulate.
I appreciate Dougs comments. After our experience in Germany all the lightweight insulations suffer from condensation and mold attack, even if ther are attempts to install vapor proof sheets. The cellulose insulation is therefore poisoned, to hinder mold attack. But as practise shows, mold attack can not be stopped by this means if it is enough condensateto moisture it up. This is only a question of time.
Otherwise the lightweight insulation can not hinder the IR radiation taking out your heat energy through the wall as solid materials like wood and stone.We checked this out by experiment (Lichtenfelser Experiment).
Temperature after 10 min shining of a red lamp bulb on the opposite site of variuos materials. From above fiberglass, polyfoam, foam glass, solid brick, wood fibre board, gypsum cardboard, solid pinewood. Thats the reality in the wall.
And so all our comparisons between additional insulated and not insulated original buildings have proved: There is no energy saving by lightweight insulation. But it will suckupalot of condensate and cause mold and illness. You will find the details here: Thermal insulation and mold attack
Otherwise the lightweight insulation can not hinder the IR radiation taking out your heat energy through the wall as solid materials like wood and stone.We checked this out by experiment (Lichtenfelser Experiment).
Ok I still don't get it. So you're saying that if cellulose is used to fill the all cavity, then heat is emitted from the interior brick to the cellulose even through there is no air space between the brick & the cellulose?
Is this a new kind of infrared radiation that can be transmitted through solid matter? Because I thought that only materials with a high Transmittance can allow IR to be transmitted through solid matter.
Or are you saying that conduction can only occur in materials that are chemically bonded?
What about air film effects?
Also, is it even relevant to say that heat transmittance is actually by radiation? Because while marketing departments like to think that guarded hot box testing & heat plate testing only measures resistance to conductive heat flow, it actually allows some heat flow by radiation. Meaning that the "R-Values" are actually indicators of some resistance to IR.
The question is, how will heat energy be transported? Some scientific words, sorry:
1st in the air there are transports of heated air by convection and infra-red radiation (IR). The IR will not warm up air, it will be absorbed and reflexed only at the surface of the material. IR is a electromagnetic wave like light - and also light will permeate air without any losses. Only if there are partcles in the air like dust and fog, light will have 'losses'. And so it is with IR.
2nd on the material surface the IR-photon will meet a molecule and contact the electron sheath. There electrons take off the energy, jump to the next sheath (the molecule will be warmed up by taking the energy) and jump back with flashing away 'another' photon (named phonon in materials). This will transport a reduced amount of energy back to the room (all warm materials over 0 Kelvin will radiate some energy away) and to its neighboured electron sheaths and so it goes on.
Thats the way the energy will be transported in materials. New research has discovered, that you can influence the direction of the heat transport in materials by magnetic field, what is a proof of the electromagnetic way of heat through material.
Summary: Heat transports mostly and in materials nearly totally are electromagnetic. And therefore only solid materials can 'moderate' this transports.
Think about how long it will take until the hot sun or heating system will warm up a cold solid house (f.e. a castle or an adobe building). Thats the effect of solid construction. And as it takes time to be warmed up it takes even time to cool off. Otherwise lightweighters can not stop the external heat in summer - and in winter the internal heat.
I know the measuring of R-values very well. What they will measure is the amount of energy the tested surface can take of a contacting warmer molecule. If you will touch a steel plate and a insulation in the room (both with room temperature) the insulation feels warmer, less molecules will take directly energy from your warmer hand surface. But it says nothing about the later transports of energy through the material. Let sun shine its electromagnetic light through a 1 cm insulation board and a 1 cm wood board. Where will you have more sun light coming through? Thats it.
So our ancestors know how to build up good houses also belonging saving energy and living comfortable.
I hope you can follow my poor english. Please ask again if you want.
(Lichtenfelser Experiment).
