How to turn a room on the top floor into a colder not so humid and deathly hot one.

In the times before electricity, a man has vast trunks of papers and documents he needs to store for a long time but hides them in a attic or the very top floor of a 3-4 story home/manor.

From what I understand books need temperature control, how would he achieve this on the top floor of a building when heat rises? Would stone or other cold conducting materials help or some building air flow thing that could make things colder up top? And yeah It has to be in the top floor its a hidden room up there was the idea, but humidity or dry hot heat like that I think would destroy paper.

  • $\begingroup$ Well, one thing to note: Whatever effect occurs would primarily affect the edges of the book, and barely the inside, if they are closed (which is usually the case). Meaning there are steps towards its destruction which do not render them unreadable. $\endgroup$
    – Battle
    Commented Jan 10, 2019 at 8:13
  • $\begingroup$ Could you provide more information on what kind of books (i.e. how long ago and for what purpose where they made) and how long you intend to preserve them? $\endgroup$ Commented Jan 10, 2019 at 8:27
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    $\begingroup$ @JulianEgner "into a colder, less humid and deadly hot, one" may be meant. Commas are not everyone's forte. $\endgroup$ Commented Jan 10, 2019 at 8:40
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    $\begingroup$ Just leave the roof off. $\endgroup$
    – Pelinore
    Commented Jan 10, 2019 at 12:30
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    $\begingroup$ Some people and institutions have figured out how to store books well for long times. For example, at the central branch of the Philadelphia Free Library James Anderson's Royal Genealogies, 1740, was in the regular stacks the last time I used it, while Johann Stumpf's 16th century Swiss Chronicle was in the rare book room, as well asa book with biographies & images of Roman Emperors so old it included the currently reigning one (Rudoplh II, I think). $\endgroup$ Commented Jan 11, 2019 at 0:58

6 Answers 6


Books do benefit from a controlled environment, but for relatively short times (a few decades), they won’t be badly damaged by the temperature in a house loft (unless you’re in a really bad part of the world, perhaps). So you may be overestimating the problem. But older books might be more fragile if they’ve not been made to more recent specs.

However, the good news is that passive cooling techniques exist and are increasingly being used in building design. Typically you need a heat chimney to force convection to draw fresh (cooler) air in from below.

A low-tech example would be a black slate roof, with good vents at the top to allow heat out, and vents into the building below to allow it to draw fresh air in from the building below.

However, in winter, your requirements are reversed, and you’ll need to close the roof vents and allow warm air from the rest of the house to heat the loft.

What techniques will work will depend on whether the house is occupied or not, as many of the more powerful passive techniques require management (e.g. altering blinds and windows as the sun moves).

You’ll also need to consider where the insulation is placed. In the U.K. a “cold roof” is the standard design (insulation between the top floor and the loft space, so the loft space is almost at outside temperature in the winter, and gets fairly hot in the summer). Adding insulation to the roof will protect the loft against the extremes of temperature.

Google will help you here, but other techniques to keep a regulated temperature in a house:

  • General insulation on the house will help, and insulation between floors should help (a loft conversion keeps/adds insulation between the old top floor and the new floor in the loft).
  • Use of naturally insulating building materials (e.g. stone or brick instead of wood)
  • Use of building materials with high specific heat capacity (stone) to even out temperature changes
  • use of external slatted shutters, shades, or verandas to allow ventilation whilst keeping the sun out of windows.

For your time period, heating is likely to be by a fire in a fireplace. The chimney will distribute heat up the building, including into the loft. Some alterations to the chimney to allow it to transfer more heat into the loft if needed would be possible.

Moisture is harder to control; wrapping the books suitably would be the best solution. Waxed Paper, leather, waxed cloth, or similar would probably suffice.

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    $\begingroup$ +1 for mentioning wrapping the books. Look at Ancient Egyptian mummification. They embalmed bodies to keep moisture away as it's one of the bigger factors in determining how quickly a body decays $\endgroup$
    – user43712
    Commented Jan 10, 2019 at 14:01
  • $\begingroup$ I'd also mention that heavy insulation between floors of the house, and heat regulation on those floors would also be of significant help (so duplicate insulation from the loft floor to the roof, rather than just moving it). Given the times specified, maybe stone/concrete floors or woollen insulation in those areas, and maybe a thatched roof? Also, verandas shading the windows to stop the sun heating upper floors directly would reduce how much heat there is to rise to the loft. $\endgroup$ Commented Jan 10, 2019 at 15:45
  • $\begingroup$ @RalphBolton thanks, good additions! I remember now being surprised when our loft conversion kept the insulation between the old top floor and the loft. $\endgroup$
    – Dan W
    Commented Jan 10, 2019 at 16:11

This is actually a major consideration in modern building design.

Known as passive building, the idea is to minimise the ecological footprint of the building. Primarily by reducing the need for active temperature controls.

Simply following these principles in the construction of the building will greatly reduce any concerns he may have about the storage of the documents. However they're largely tied to modern principles and technology like insulation and double glazing.

He has some advantages though, the dry heat of a fire tends to reduce condensation in a way that central heating doesn't. The chimney of his building probably runs up through the space he's using for storage meaning that through the winter the room will be warmed by the fires below. A thatched roof will also offer greater temperature control than slate, reducing the range of temperatures the documents are exposed to.

Stone is good as thermal mass, but external stone tends to attract condensation on the inside, so it would be good for a chimney where it would hold heat for long periods, but not great for external walls where it would encourage mold. Better to use wattle and daub with its better insulating properties.


This is pretty easy and widely managed even today by some peoples cooling their homes in hot countries.

Work out where the prevailing wind comes from, build a ladder access floorless room on the roof which opens into the prevailing wind and funnels the air down into the house. If it gets too cold, close the door. If you get wind from a different direction like a seabreeze at certain times, have a another door. Normally you get a fairly steady dust free breeze and the higher your roof room the better.

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    $\begingroup$ Actually works better and more controllably to do the opposite: put the opening on the leeward side, and the low-pressure zone the building creates in its wind shadow as the prevailing wind passes by will draw out the heated air. Very common in passively cooled structures. $\endgroup$ Commented Jan 10, 2019 at 16:32
  • $\begingroup$ @GerardFalla sounds reasonable, but it's actually been done the described way for thousands of years in places with a steady prevailing wind $\endgroup$
    – Kilisi
    Commented Jan 10, 2019 at 22:04
  • $\begingroup$ In fact in Persia where windtraps were first thoroughly codified, both approaches were and are common: also square in plan towers far above primary roof height (and therefore interior airmass highpoint) with four ducted openings with louvers controlled by connecting rods - allows you to tune response based on time of day, direction of wind etc. the other advantage of leewards / low pressure side venting is less dust & other particulates infiltrating the building envelope. $\endgroup$ Commented Jan 10, 2019 at 22:23
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    $\begingroup$ Yup = too right. Here's a project I was deeply involved in which did (and does) use the stack venting effect (a.k.a. thermosyphon) to great effect - the student love the space and how it feels. mogaveroarchitects.com/… $\endgroup$ Commented Jan 10, 2019 at 22:32
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    $\begingroup$ What we did in that case I shared the link to was have the in-space venting set under window seats at the student's small shared mini-lounges... made it easy to have simple louver controls in the vents - minus other mechanical flow boosts. It's in Davis, which gets hot in the summer... and the Tercero dorms stay lovely and fresh even when it's spanking hot outside, and though there is mechanical AC there if needed, all the post-occupancy data clearly show significantly lower needed AC use than other nearby dorms of similar size. $\endgroup$ Commented Jan 10, 2019 at 23:00

In addition to constructing the building in a certain way, he could seal the books in thick-walled clay pots.

A good starting point is a pot or amphora with a lid made of burned clay. Place the books inside and seal the lid with fresh clay (of course you cannot burn it with the books inside).

The clay evens out changes in temperature and humidity and keeps insects out that might otherwise destroy the books. They do not work like an air condition, but they should protect the books better than lying in open shelves.

If you need to access the books inside, you carefully scratch the seal of unburned clay away from the lid. Due to the difference in hardness between burned and unburned clay, they should be easy enough to seperate.

The risk of this method is that moisture in the pots (like from a leaking roof) causes the books to rot (or get mouldy) faster than without a pot because they take longer to dry.


If you just want to store your books, the hot room at the top is good as it is. Books burn at Fahrenheit 451 / 232 Celsius. Your Room would not get so hot. What kills books is mostly humidity, wich will be much less in a hot room at the top. And of course you must prevent exposition to sunlight, because that would destroy the ink on the paper.

If you really want to cool down a room, you can use two things:

  • water and evaporation (but outside the room and you must save your books against humidity)
  • Ice Blocks. Before electric fridges came up, Ice was cut in the winter and was used to cool already cool rooms (icebox). I do not know if this was already made in medieval ages, but it should be possible.
  • $\begingroup$ Moisture is definitely a problem, but modern commercial paper is high in lignin, which is acidic and causes the paper to degrade; the higher the temperature, the faster it degrades. Hot air can also carry more humidity, so a hot environment would have moisture issues. Assuming the ink uses pigments instead of dyes, sunlight would damage the paper more than the ink. A closed-system, passive heat pump would be a good way to control the temperature. BTW: Romans harvested and stored ice blocks so, yes, the technology was available in medieval societies. $\endgroup$
    – Suncat2000
    Commented Jan 10, 2019 at 13:22
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    $\begingroup$ @Suncat2000 "modern commercial paper" doesn't fit with "the times before electricity". Large scale use of wood pulp in paper didn't start until 1840 - before that, it was all based on cotton rags - and that doesn't have a high lignin content. $\endgroup$ Commented Jan 10, 2019 at 15:28

This answer assumes you want to keep the books safe for generations and live in a warm climate.

According to the Wikipedia article on the conservation and restoration of books, manuscripts, documents and ephemera, there are the following elements that constitute to the degredation of paper et al. (highlighting is my own):

  1. Inherent vice

    Inherent vice is "the quality of a material or an object to self-destruct or to be unusually difficult to maintain". Paper, books, manuscripts, and ephemera are prime examples of materials subject to inherent vice.

The typical "old book smell" would be a classic example of chemicals and materials in the book that break down over time. Since these are primarily chemical reactions, cooling storage would be (as you pointed out) beneficial.

  1. Pest

    Insects and vermin are naturally attracted to paper because paper is made of cellulose, starch and protein, materials that provide sources of nourishment. [...] To best discourage infestation, a clean and dust-free environment is desirable: food and drink should be kept away from storage areas.

This may be seen in the form of blotches or other blemishes on pages, but can also be visible in other ways.

  1. Environmental conditions

    Extremes of temperature or relative humidity are damaging from either end of the spectrum (low or high). [...]

    Fluctuations in temperatures and humidity may also cause cockling: a wrinkling or puckering preventing the surface from laying flat. [...]

    Dust tends to absorb moisture, providing a suitable environment to attract mold growth and insects. Dust can also become acidic when combined with skin oils and the surface of paper. [...]

    All kinds of light (sunlight, artificial light, spotlights) can be harmful. Light can result in fading, darkening, bleaching, and cellulose breakdown. Some inks and other pigments will fade if exposed to light, especially ultraviolet (UV) light present in normal daylight and from fluorescent bulbs. [...] Minimal or no exposure to light is ideal.

Extreme temperatures and humidity can result in leather cracking, rotting and other nasty things.

Keeping humidity ideal will be difficult, as will keeping the environment stable and reducing dust.

Light won't be much of a problem for the books, since a hidden room seldom has windows and artificial light before electricity would be dangerous anyway, so you simply leave the room dark. The problem with light would be one's inability to see anything, making cleaning and managing storage, let alone reading, a challenging task.

Therefore we are left with the following conditions for the ideal room:

  1. Cool (below ca. 20 C°/70 F°)

  2. Dry-ish (30-50% humidity)

  3. Clean (no dust, no life)

  4. Dark (as little light as possible)

The first two we can measure using thermometers and hygrometers both of which would have been available before electricity (there are some really interesting designs, I would recommend doing a little research on the subject). You could have them both measuring the room while displaying the values outside of it, allowing 'remote' observation to regulate manually.

Self-regulating mechanical systems would be possible but quite probably unreliable and highly complex. You could perhaps construct an alerting system connected to the meters that makes a wound-up bell go of or something of the sorts, should the values become out-of-bounds.

To regulate temperature you could use many different methods as found on the site of the Permaculture Research Institute. Your ideal solution will depend on the climate of your region.

To regulate humidity you could use ventilation methods, causing water to evaporate so you can vent it via a skylight et al., or use absorbing materials such as charcoal or rock salt in large amount. Regulation would be done by adjusting the airflow or the amount/freshness of the absorbent material.

To keep your room clean you could seal your room as well as possible, reducing the risk of pests or dust entering the room, before killing everything off via your method of choice. This may include super-heating, freezing, suffocating (if the room is airtight) or using chemicals. If you decide to use chemicals, make sure you can remove all traces of it from the room to prevent damage to the books and poisoning yourself.

After you're sure everything is dead, do a spring clean of the room, making sure all parts of the room are easily accessible and as clean as possible. Move in your books after inspecting them for potential risks.

To prevent light I would probably build in a small, sealed 'window' that shines past the books. You can the use the ambient sunlight to do your work while keeping the amount of light as low as possible.

I hope this answer contains some inspiration for your final solution.


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