diff --git a/src/interval_set.rs b/src/interval_set.rs
index 6a059e3..acc6a74 100644
--- a/src/interval_set.rs
+++ b/src/interval_set.rs
@@ -91,7 +91,7 @@ impl IntervalSet {
     }
 
     pub fn merge(&mut self, other: &IntervalSet) {
-        self.0.extend(other.0.clone());
+        self.0.extend(other.0.iter().cloned());
         self.coalesce();
     }
 
diff --git a/src/lib.rs b/src/lib.rs
index 79945dd..569ba5d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -14,6 +14,7 @@ use crate::executors::*;
 use crate::interval::*;
 use crate::interval_set::*;
 use crate::requirement::*;
+use crate::resource_interval::*;
 use crate::schedule::*;
 use crate::storage::*;
 use crate::task::*;
@@ -27,6 +28,7 @@ pub mod executors;
 pub mod interval;
 pub mod interval_set;
 pub mod requirement;
+pub mod resource_interval;
 pub mod schedule;
 pub mod storage;
 pub mod task;
diff --git a/src/resource_interval.rs b/src/resource_interval.rs
new file mode 100644
index 0000000..ab36f15
--- /dev/null
+++ b/src/resource_interval.rs
@@ -0,0 +1,66 @@
+use super::*;
+use std::ops::{Add, Deref, DerefMut, Sub};
+
+/// Contains a map of resource and intervals. The intervals could
+/// represent where a resource is available, or where it's required
+/// Resources are independent, so overlaps between the
+/// interval sets are possible.
+pub struct ResourceInterval(HashMap<Resource, IntervalSet>);
+
+impl ResourceInterval {
+    fn new() -> Self {
+        ResourceInterval(HashMap::new())
+    }
+}
+
+impl Deref for ResourceInterval {
+    type Target = HashMap<Resource, IntervalSet>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl DerefMut for ResourceInterval {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl From<HashMap<Resource, IntervalSet>> for ResourceInterval {
+    fn from(hm: HashMap<Resource, IntervalSet>) -> Self {
+        ResourceInterval(hm)
+    }
+}
+
+impl From<&HashMap<Resource, IntervalSet>> for ResourceInterval {
+    fn from(hm: &HashMap<Resource, IntervalSet>) -> Self {
+        ResourceInterval(hm.clone())
+    }
+}
+
+impl Add for &ResourceInterval {
+    type Output = ResourceInterval;
+    fn add(self, other: &ResourceInterval) -> Self::Output {
+        let res: HashMap<Resource, IntervalSet> =
+            other.0.iter().fold(self.0.clone(), |mut acc, (res, is)| {
+                acc.entry(res.clone())
+                    .or_insert(IntervalSet::new())
+                    .merge(is);
+                acc
+            });
+        ResourceInterval(res)
+    }
+}
+
+impl Sub for &ResourceInterval {
+    type Output = ResourceInterval;
+    fn sub(self, other: &ResourceInterval) -> Self::Output {
+        let res: HashMap<Resource, IntervalSet> =
+            other.0.iter().fold(self.0.clone(), |mut acc, (res, is)| {
+                acc.entry(res.clone())
+                    .or_insert(IntervalSet::new())
+                    .difference(is);
+                acc
+            });
+        ResourceInterval(res)
+    }
+}