diff --git a/src/main/java/io/orprotocol/Stream.java b/src/main/java/io/orprotocol/Stream.java
index c1c01c7..08fc0af 100644
--- a/src/main/java/io/orprotocol/Stream.java
+++ b/src/main/java/io/orprotocol/Stream.java
@@ -28,14 +28,16 @@ public class Stream {
     public void writeInt8(int value) {
         int negationBit = value < 0 ? 1 : 0;
         int int8Value = Math.abs(value) & 0xFF;
-        
-        ensureCapacity(writePointer >> 3);
+        /**
+         * 1 sign
+         * 8 bits for value
+         */
+        reserveBits(9);
         stream[writePointer >> 3] |= (byte) (negationBit << (7 - (writePointer & 7)));
         writePointer++;
         
         for (int i = 0; i < 8; i++) {
             int bit = (int8Value >> (7 - i)) & 1;
-            ensureCapacity(writePointer >> 3);
             stream[writePointer >> 3] |= (byte) (bit << (7 - (writePointer & 7)));
             writePointer++;
         }