diff --git a/providers/ec2/manifest.py b/providers/ec2/manifest.py
index d2e0f2c..01813a7 100644
--- a/providers/ec2/manifest.py
+++ b/providers/ec2/manifest.py
@@ -1,4 +1,5 @@
 import base
+from common.exceptions import ManifestError
 
 
 class Manifest(base.Manifest):
@@ -7,9 +8,14 @@ class Manifest(base.Manifest):
 		from os import path
 		schema_path = path.join(path.dirname(__file__), 'manifest-schema.json')
 		self.schema_validate(data, schema_path)
+		if data['volume']['backing'] == 'ebs' and data['volume']['size'] % 1024 != 0:
+			msg = 'The volume size must be a multiple of 1024 when using EBS backing'
+			raise ManifestError(msg, self)
 
 	def parse(self, data):
 		super(Manifest, self).parse(data)
 		self.credentials    = data['credentials']
 		self.virtualization = data['virtualization']
 		self.image          = data['image']
+		if data['volume']['backing'] == 'ebs':
+			self.ebs_volume_size = data['volume']['size'] / 1024
diff --git a/providers/ec2/tasks/ami.py b/providers/ec2/tasks/ami.py
index fbabbf3..575527c 100644
--- a/providers/ec2/tasks/ami.py
+++ b/providers/ec2/tasks/ami.py
@@ -66,7 +66,7 @@ class RegisterAMI(Task):
 		from boto.ec2.blockdevicemapping import BlockDeviceType
 		from boto.ec2.blockdevicemapping import BlockDeviceMapping
 		block_device = BlockDeviceType(snapshot_id=info.snapshot.id, delete_on_termination=True,
-		                               size=int(info.manifest.volume['size']/1024))
+		                               size=info.manifest.ebs_volume_size)
 		block_device_map = BlockDeviceMapping()
 		block_device_map['/dev/sda1'] = block_device
 
diff --git a/providers/ec2/tasks/ebs.py b/providers/ec2/tasks/ebs.py
index 453fe29..49e5ba5 100644
--- a/providers/ec2/tasks/ebs.py
+++ b/providers/ec2/tasks/ebs.py
@@ -10,9 +10,8 @@ class CreateVolume(Task):
 	phase = phases.volume_creation
 
 	def run(self, info):
-		volume_size = int(info.manifest.volume['size']/1024)
-
-		info.volume = info.connection.create_volume(volume_size, info.host['availabilityZone'])
+		info.volume = info.connection.create_volume(info.manifest.ebs_volume_size,
+		                                            info.host['availabilityZone'])
 		while info.volume.volume_state() != 'available':
 			time.sleep(5)
 			info.volume.update()