Can LEGO be damaged by heat/cold extremes?

[AMK152]

Okay, I have read through this thread, but I still haven't found my answer.

I have always kept my bricks in an environment that doesn't get too warm. I have had them in room temperature (1995-2000), then in my basement (2000-2011). The temperature in the basement wasn't too cold (perhaps as low as 40-50 degrees F). I had no issues with cracking, but some of my older pieces had lost their clutching power (but not too much; there is only one piece that doesn't clutch anymore, out of perhaps 40,000 bricks). Then in 2011, had some flooding issues and the basement was smelly and the walls inside my LEGO room were affected with mildew. I ended up "evaucating" my bricks into storage tubs back to room temperature and had some on display on a 2' by 8' table since December 2013. Now, I want to recreate my LEGO city (I used to have 73 square feet of table space for my city).

The thing is, the best place to place my city is in the attic (the basement is no longer an option). However, it gets very cold in the winter and very warm in the summer. The attic is not insulated and it generally follows this:

January - February: low ranges from about 0s to 30s F

March - June: average temperature between 30s and 70s F

July - August: temperatures get as high as 110s F

September - October: average temperature between 30s and 70s F

November - December: low ranges from 0s to 30s F

Very rarely is there a sharp change in temperature, it's all very gradually throughout the year. The cold months are somewhat bearable, although I would not want to be up there longer than 20 minutes without freezing. In the hotter months (July/August), I don't like to be up there because I can barely breath. I can probably stand it for 10 minutes, maybe longer if I had a fan running, but these temperatures only last for a couple of months.

My question is, will my bricks be okay in this cycle? I am not talking about for storage, I am talking for actual display and building, along with sets put together. Some of the buildings I have put together are 14-15 years old, and my oldest bricks were purchased in 1995, although most of the bricks in my collection were purchased between 1999 and 2007. Will my bricks be okay?

Edited December 1, 2014 by AMK152

[Wodanis]

Honestly I would insulate your attic if you plan on displaying your sets there. The fluctuations in temperature will reduce clutch power and affect bricks while built. I had a forest men set built in my closet for 20 years and the pieces were expanding and contracting with the temperature gradually. -10 degrees Celsius and below is not recommended for bricks as is plus 30 degrees. It you plan on storing in your attic leave the bricks separated to ease the expansion and contraction.

[srw]

For loft storage, I wonder if it is better to store lego in (thick) cardboard boxes or plastic storage boxes?  Plastic boxes in the winter would keep out moisture but plastic boxes in the summer just seem to retain more heat than a cardboard box and can pass on a smell to the bricks.

Just to clarify (and maybe I should buy Gerhards guide) will bricks go yellow from heat or is the yellow only from UV light?

 

P.S. Its a really hot day today here in England.

Edited July 26, 2018 by srw