Okay. Normally, that would simply cause your building to deteriorate into thin air. If you want it to blow up, add these lines:
<killedLeavings>
<Fire>1</Fire>
<Boom>1</Boom>
</killedLeavings>
"Boom" is an new object you create that will have 1hp and flammability. Add something like this to your object:
<comps>
<li Class="CompProperties_Explosive">
<explosiveRadius>6.9</explosiveRadius>
<explosiveDamageType>Bomb</explosiveDamageType>
<explosiveExpandPerStackcount>1.2</explosiveExpandPerStackcount>
<startWickHitPointsPercent>0.333</startWickHitPointsPercent>
<wickTicks>
<min>30</min>
<max>70</max>
</wickTicks>
</li>
</comps>
When your building is hotter than 20 Celsius, it will deteriorate until it drops a flame and an explosive object. The fire will ignite the object, causing an explosion even in the rain.
<killedLeavings>
<Fire>1</Fire>
<Boom>1</Boom>
</killedLeavings>
"Boom" is an new object you create that will have 1hp and flammability. Add something like this to your object:
<comps>
<li Class="CompProperties_Explosive">
<explosiveRadius>6.9</explosiveRadius>
<explosiveDamageType>Bomb</explosiveDamageType>
<explosiveExpandPerStackcount>1.2</explosiveExpandPerStackcount>
<startWickHitPointsPercent>0.333</startWickHitPointsPercent>
<wickTicks>
<min>30</min>
<max>70</max>
</wickTicks>
</li>
</comps>
When your building is hotter than 20 Celsius, it will deteriorate until it drops a flame and an explosive object. The fire will ignite the object, causing an explosion even in the rain.