Warforged Composition
Warforged are formed in the creation forges, which channel the powers of Cannith heirs to produce effects similar to major creation and fabricate. The materials of the warforged are not truly natural; this is reflected by the ability of a warforged juggernaut to change its shape over time (growing spikes), or the fact that an armorer can repair a mithral warforged even when he doesn't have any mithral on hand. An important side effect of this is that if material is removed from the body of a warforged, it quickly degrades. As a result, stripping a warforged and selling its metal is impossible; a warforged may have adamantine components, but these will rust and pit when they are pulled from the warforged.
The warforged are made using a blend of materials. The core of a warforged is a frame formed from wood, stone, or metal. Bundles of rootlike fibers surround the core and serve as the muscles of the construct. Plates of steel and wood are fused over this layer of tendrils, forming the hard outer shell of the warforged. The precise appearance and construction of the body depends on the model of the warforged, as represented by its initial feats. This also affects the weight of the warforged, as shown below.
Composite Plating: A warforged with the default composite plating has a base height of 5'10", with a +2d6 height modifier, base weight of 270 pounds, and weight modifier of x4.
Adamantine Body: Its base weight is 320 pounds, with a weight modifier of x6. While adamantine itself is no heavier than steel, a warforged with this feat is typically more massive than other models, with more steel and stone in its construction.
Darkwood Body or Mithral Body: Its base weight is 180 pounds, with a weight modifier of x2. These materials are unusually light, and these warforged tend to be lean and flexible. *edit* base weight is 255 pounds , with a weight modifier of x2.
Unarmored Body: Its base weight is 225 pounds, with a weight modifier of x3. A warforged with this feat is covered with composite plating, but these plates are extremely thin and do not interfere with movement or spellcasting.